National Academies Press: OpenBook
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Page 1
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 1
Page 2
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 2
Page 3
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 3
Page 4
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 4
Page 5
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 5
Page 6
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 6
Page 7
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 7
Page 8
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 8
Page 9
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 9
Page 10
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 10
Page 11
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 11
Page 12
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 12
Page 13
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 13
Page 14
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 14
Page 15
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 15
Page 16
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 16
Page 17
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 17
Page 18
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 18
Page 19
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 19
Page 20
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 20
Page 21
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 21
Page 22
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 22
Page 23
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 23
Page 24
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 24
Page 25
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 25
Page 26
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 26
Page 27
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 27
Page 28
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 28
Page 29
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 29
Page 30
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 30
Page 31
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 31
Page 32
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 32
Page 33
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 33
Page 34
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 34
Page 35
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 35
Page 36
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 36
Page 37
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 37
Page 38
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 38
Page 39
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 39
Page 40
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 40
Page 41
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 41
Page 42
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 42
Page 43
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 43
Page 44
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 44
Page 45
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 45
Page 46
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 46
Page 47
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 47
Page 48
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 48
Page 49
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 49
Page 50
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 50
Page 51
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 51
Page 52
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 52
Page 53
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 53
Page 54
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 54
Page 55
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 55
Page 56
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 56
Page 57
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 57
Page 58
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 58
Page 59
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 59
Page 60
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 60
Page 61
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 61
Page 62
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 62
Page 63
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 63
Page 64
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 64
Page 65
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 65
Page 66
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 66
Page 67
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 67
Page 68
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 68
Page 69
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 69
Page 70
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 70
Page 71
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 71
Page 72
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 72
Page 73
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
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Page 74
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 74
Page 75
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 75
Page 76
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 76
Page 77
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 77
Page 78
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 78
Page 79
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 79
Page 80
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 80
Page 81
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 81
Page 82
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 82
Page 83
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 83
Page 84
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 84
Page 85
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 85
Page 86
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 86
Page 87
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 87
Page 88
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 88
Page 89
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 89
Page 90
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 90
Page 91
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 91
Page 92
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 92
Page 93
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 93
Page 94
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 94
Page 95
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 95
Page 96
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 96
Page 97
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 97
Page 98
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 98
Page 99
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 99
Page 100
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 100
Page 101
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 101
Page 102
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 102
Page 103
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 103
Page 104
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 104
Page 105
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 105
Page 106
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
Page 106
Page 107
Suggested Citation:"Part I - General Literature Review." National Academies of Sciences, Engineering, and Medicine. 2005. Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work. Washington, DC: The National Academies Press. doi: 10.17226/13839.
×
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Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Part I General Literature Review

Since 1995, the U.S. Department of Transportation’s Federal Motor Carrier Safety Administration (FMCSA) (formerly FHWA’s Office of Motor Carriers) actively con- ducted a program of research, study, and industry outreach and education on commer- cial motor vehicle (CMV) driver alertness, fatigue, health, and wellness. There was much open public discussion, deliberation, and negotiation over the public rulemaking process from 1996 to 2003. In May 2003, FMCSA issued new hours of service (HOS) rules for CMV drivers with a planned implementation date of January 2004. After sub- stantial amounts of training and preparation by government and the trucking industry, those new HOS rules went into effect January 4, 2004. The January 2004 revised HOS rules extended allowable driving time to 11 hr and cut overall driver work to 14 hr before requiring a 10-hr break. The old HOS rules lim- ited CMV driving to 10 hr, and allowed drivers to work 15 hr before taking a manda- tory 8-hr break. Public Citizen challenged those HOS rules in a lawsuit, alleging that the new HOS did not properly account for CMV driver health concerns. Responding to that lawsuit, in July 2004, the U.S. Court of Appeals for the Washington, D.C., Circuit ruled that DOT’s FMCSA did not follow a congressional mandate to consider truck drivers’ health in the revised HOS rules. FMCSA requested the federal court to stay its order and keep the current, revised HOS rules in effect until FMCSA can re-present its case or prepare a new set of HOS rules. As one part of its efforts to reply to the Court of Appeals ruling on HOS, FMCSA requested the independent technical assistance from a third-party research team. FMCSA asked MaineWay Services to summarize the scientific and technical literature on CMV operator health, wellness, fatigue, and performance, as they relate to the hours a person works, or to the structure of the work schedule (e.g., on-duty/off-duty cycles, sleep time, etc.). The MaineWay Services research team was assigned the task of literature review. This synthesis is designed to provide information to FMCSA on existing literature in this subject area. SUMMARY LITERATURE REVIEW ON HEALTH AND FATIGUE ISSUES ASSOCIATED WITH COMMERCIAL MOTOR VEHICLE DRIVER HOURS OF SERVICE

OBJECTIVES AND SCOPE This synthesis responds to the statement of work (see Appendix A): to review the scientific and technical literature in two topical areas related to HOS: (1) driver health and (2) driver fatigue. Driver Health. The synthesis reviews and summarizes available information in the sci- entific and technical literature concerning HOS and CMV operator health. The purpose of the literature review was to provide information that clearly discusses in a scientific, experimental, quantitative, or qualitative way, the relationship between the hours a per- son works or the structure of the work schedule (e.g., on-duty/off-duty cycles, sleep time, etc.) and the impact on some medical conditions of concern to truck drivers. The literature review summarizes the characteristics and methodology of each study, so that each study’s approach can be clearly understood and compared with other studies. Driver Fatigue. The synthesis reviews and summarizes available information in the scientific and technical literature concerning HOS and CMV operator performance and fatigue, especially as they pertain to driver health. The purpose of this facet of the lit- erature review is to provide information that clearly summarizes in a scientific, exper- imental, qualitative, and quantitative way the relationship between the hours a person works, drives, and the structure of the work schedule (on-duty/off-duty cycles, time on task, especially time in continuous driving, sleep time, etc.) and the impact of CMV driver fatigue and performance. The literature review summarizes the characteristics and methodology of each study, so that each study’s approach can be clearly under- stood and compared with other studies. SELECTION OF AND PARTICIPATION OF KEY PERSONNEL ON THE PROJECT Following award of the contract for this research, Gene Bergoffen, Principal, MaineWay Services, appointed two technical panels, one on driver health and the other on driver fatigue. Mr. Bergoffen served as the project executive administrator and senior advisor, with the assistance of Gerald P. Krueger, PhD., as the senior technical advisor. After consultation with the FMCSA, Peter Orris, MD, MPH, was appointed as technical advisor and panel leader for the health literature review and Alison Smiley, PhD., was appointed as technical advisor and as the panel leader for the fatigue literature review. The background of the key project personnel is included in the following section. Dr. Orris was assisted by Dr. Susan Buchanan. To provide additional peer input and advice in the health literature review, Dr. Orris elicited panel member participation from four additional experts listed in the Health Panel Members section. Ms. Smiley was assisted by Dianne Davis. To provide further input and advice in the fatigue liter- ature review, Ms. Smiley elicited panel member participation from two additional experts listed in the Fatigue Panel Members section. KEY PERSONNEL Project Administration Gene Bergoffen, MaineWay Services, Project Administrator and Senior Advisor • Currently the Principal of MaineWay Services, a transportation research and con- sulting firm in Fryeburg, Maine 4

5• Eight years as President and CEO, National Private Truck Council • Co-investigator and co-author of CTBSSP Synthesis 1, “Effective Commercial Truck and Bus Safety Management Techniques” • Leader of MaineWay Services Task Order Team for several CTBSSP Synthesis Projects; principal investigator of CTBSSP Synthesis 8, “Commercial Motor Vehicle Driver Safety Belt Usage” • Broad experience in project management stemming from the organization of the Private Fleet Management Institute and including a number of research projects conducted when employed by Science Applications International Corporation Gerald P. Krueger, PhD, Wexford Group International, Senior Technical Advisor Highly experienced engineering psychologist and human factors specialist (36 years) and a Certified Professional Ergonomist (CPE) • Recognized authority on sustained performance of aviators, heavy equipment operators, and of CMV driver fatigue, factors relating to driver wellness and health, and occupational and environmental medicine research • Co-investigator on two truck driver simulator studies and one large field study on CMV truck driver alertness and fatigue issues • Principal developer of two FMCSA and American Trucking Associations’ (ATA) train-the-trainer courses: Mastering Alertness and Managing Commercial Driver Fatigue; and Gettin’ in Gear Wellness, Health and Fitness for Commercial Drivers • Co-investigator and co-author for CTBSSP Synthesis 7, “Motorcoach Industry Hours of Service and Fatigue Management Techniques.” • Co-investigator and principal ergonomist on CTBSSP Synthesis 8, “Commercial Motor Vehicle Driver Safety Belt Usage” Health Panel Peter Orris, MD, MPH • Professor of Occupational and Environmental Health Sciences, University of Illi- nois School of Public Health, Cook County Hospital • Director of Occupational Health Services Institute, Great Lakes Center for Occu- pational and Environmental Safety and Health, University of Illinois • Chief of Service, Occupational and Environmental Medicine, University of Illi- nois at Chicago Hospital and Medical Center • President, Medical Staff, Cook County Hospital • Secretary/Treasurer, Journal of Public Health Policy • Member of Medical Advisory Committee of International Brotherhood of Teamsters • Author of multiple publications relating to public health topics and reviewer and participant in editorial boards of a range of professional journals related to pub- lic health topics Susan Buchanan, MD, MPH • Interim Program Director, Occupational Medicine Residency, University of Illi- nois at Chicago College of Medicine • Author, several publications relating to Occupational Health • Reviewer, American Journal of Industrial Medicine, 2004

Health Panel Members • Leslie Stayner, PhD. – Professor and Director, Epidemiology and Biostatistics, University of Illinois, Chicago School of Public Health – Served as Chief of Risk Evaluation Branch, National Institute for Occupational Safety and Health, Education and Information Division, and in several other career positions relating to risk evaluation – Contributing Editor to Journal of Industrial Medicine and involved in a wide range of professional activities relating to industrial health • Eric Garshick, MD, MOH – Assistant Professor of Medicine, VA Boston Healthcare System, Channing Laboratory, Brigham and Women’s Hospital, Harvard Medical School – Served as Advisor, World Health Organization. International Program on Chem- ical Safety, Environmental Health Criteria for Diesel Fuel and Exhaust Emis- sions, Geneva, Switzerland – Served as consultant, U.S. EPA Science Advisory Board, Clean Air Scientific Advisory Committee Diesel Emissions Health Document • William Marras, PhD. – Co-Director, Institute of Ergonomics, Ohio State University – Professor, Department of Physical Medicine, Biomedical Engineering Center, Ohio State University – Associate Editor, Human Factors • Natalie Hartenbaum, MD, MPH – President and Chief Medical Officer of OccuMedix, Inc. – Adjunct Assistant Professor of Emergency Medicine/Occupational Medicine at the University of Pennsylvania – Editor-in-Chief of CDME (Commercial Driver Medical Examiner) Review Fatigue Panel Alison Smiley, PhD. • President of Human Factors North, Inc., a Toronto-based human factors and engineering consulting company; and a Canadian Certified Professional Ergono- mist (CCPE) • 30 years experience in measurement of human performance, and human fac- tors consulting, specializing in driver behavior, transportation safety, and shift work • Senior specialist in assessment of work-rest schedules, shift work, hours of work and worker rest for transportation industries (railways, coast guard and marine vessels, trucking, etc.) and for nuclear power plant and manufacturing operations • Project manager for several Transport Canada projects involving literature review and development of experimental protocols related to fatigue and minimum recovery periods for CMV drivers • Forensic consultant with expertise on car and truck driver fatigue and shift- scheduling issues • Consultant to both Canadian and U.S. governing bodies on trucking industry HOS regulations 6

7Dianne Davis, M.Eng • Associate Consultant, Human Factors North, Inc. • More than 10 years experience conducting human factors analyses in a variety of different domains such as the safety of driver examination tests, the study of fatigue and truck driving, way-finding, and the design of medical mobile devices and online shipping tools Fatigue Panel Members • Mark Rosekind, PhD. – President and Chief Scientist, Alertness Solutions, Cupertino, California – Served as Research Scientist and Team Leader, Fatigue Countermeasures Pro- gram, Aviation Safety Research Branch, Flight Management and Human Fac- tors Division, NASA Ames Research Center • Richard Hanowski, PhD. – Leader, Truck and Bus Safety Group, Virginia Tech Transportation Institute – Experience includes transportation human factors with both heavy and light vehicles, laboratory and field testing, real-time automobile and heavy vehicle simulation, advanced system development and testing, design guideline devel- opment, and human performance evaluation ORGANIZATION AND PRESENTATION OF PART I: GENERAL LITERATURE REVIEW The literature review is presented in two sections: Health and Fatigue. The health literature review has the following subsections: • Executive summary, • Process and methodology, • Selection criteria, • Review of primary sources, • Article summaries, • Summary of findings of literature, and • Bibliography of primary and secondary sources. The fatigue literature review has the following subsections: • Process and methodology, • Selection criteria, • Article summaries, • Summary of findings of literature, • Research limitations, • Complete primary sources and abstracts, and • Secondary sources. Appendix A of the synthesis presents the initial FMCSA prescribed statement of work. As called for in this statement, the team consulted with FMCSA on the ultimate make-up of the two literature review panels and on all other elements of the synthesis. Two briefings of the FMCSA staff were conducted during the course of the study to gain feedback on methodology, scope, and initial findings.

LITERATURE REVIEW—HEALTH EXECUTIVE SUMMARY The purpose of this literature review is to provide infor- mation that clearly discusses in a scientific, experimental, qualitative, and quantitative way the relationship between the hours a person works, drives, and the structure of the work schedule (on-duty/off-duty cycles, time on task, especially time in continuous driving, sleep time, etc.) and the impact on the health of truck drivers. The PubMed access service was used for the literature search. PubMed was developed by the National Center for Biotechnology Information (NCBI) at the National Library of Medicine (NLM), located at the National Institutes of Health (NIH). The database contains bibliographic citations and author abstracts from more than 4,800 biomedical jour- nals published in the United States and 70 other countries and is available via the NCBI Entrez retrieval system. The initial search resulted in more than 1,850 articles. After screening and comparison with the questions to be answered in this exercise, 55 articles were reviewed. Twenty-five arti- cles were chosen and summarized by a primary reviewer to be included in the synthesis based on the validity of the method- ology, the relevance of the studied population to truck driving, and the quality of the statistical analysis of health outcomes. This review excluded those end points of fatigue, accidents, and road safety. The team evaluated the available information concerning driver health, with emphasis on chronic condi- tions, potentially associated with the 2003 HOS Regulations under consideration by the FMCSA. Findings from the Literature The following findings were drawn from the available lit- erature reviewed as part of this synthesis. • Lung cancer is likely caused by exposure to diesel exhaust and the longer that exposure lasts the more likely it is that a cancer will develop. Though the evidence linking this exposure to bladder cancer is less robust than that to lung cancer, it remains likely that there is such a rela- tionship and that it is governed by a positive dose- response curve. • There is some evidence that cardiovascular disease is caused in part by truck driving and its risk increases with the duration of this activity and the disruption of the sleep cycle. • Based on exposure assessments, noise-induced hearing loss could well be a result of a working lifetime as a dri- ver. This effect would be mitigated by the improvement in cab design reported to be occurring with consequent reduction in the intensity of noise reaching the driver. • The evidence concerning a relationship between whole- body vibration (WBV) and musculoskeletal effects, such as low back pain (LBP) syndrome, relies primarily on self-reporting and application of risks derived from other environments. There are several studies available though that contain objective evidence of vertebral path- ology related to an occupation as a professional driver. In conclusion, the available data support the hypothesis that there is likely a causative relationship between pro- fessional driving and a variety of vertebral disorders as well as LBP syndrome. While the literature suggests a role for WBV in the genesis of these disorders, it cannot be established based on current published materials. • The literature related to commercial driving and other musculoskeletal disorders has the same limitations as the previous item, and while a causative relationship is logical, it can only be viewed as suggestive within this context. • Gastrointestinal (GI) disorders would be expected to be impacted by varying shift assignments and disruption to normal circadian rhythm. While the information cur- rently available documents an increase in symptoms in drivers, it is inadequate to implicate the specific risk fac- tors that impact on these symptoms. • The literature suggests, but does not establish, that dis- ruption of circadian rhythm may have negative impacts on the general health of workers. The stabilization of shift especially when stabilized to a day schedule appears to have a beneficial effect on subjective health com- plaints though stabilizing to an evening or night sched- ule may not provide the same benefit. • Finally, the literature contains no definitive information concerning (a) the relationship between reproductive health and duration of driving, (b) the effects of pro- longed work hours, or (c) increasing driving from 10 to 11 hr while decreasing overall work time from 15 to 14 hr on the general health of workers. No data are avail- able concerning the effects of allowing for increased sleep time from 6 to 8 hr in an adult working population. 8

9PROCESS AND METHODOLOGY Literature Search Source and Terms The PubMed access service was used for the literature search. PubMed was designed to provide access to citations from biomedical literature, including bibliographic informa- tion that includes MEDLINE. MEDLINE is the NLM’s pre- mier bibliographic database covering the fields of medicine, nursing, dentistry, veterinary medicine, the health care sys- tem, and the preclinical sciences. MEDLINE contains bibli- ographic citations and author abstracts from more than 4,800 biomedical journals published in the United States and 70 other countries. The database contains more than 12 million citations dating back to the mid-1960s. Coverage is world- wide, but most records are from English-language sources or have English abstracts. A search for articles after 1975 was performed on the data- base using the following terms: Health effects and the following • Commercial vehicle operator • Commercial driver • Driver occupation • Vibration and motor vehicle Based on the results from these searches, each of the search terms—motor vehicle operator, truck driver, occupation— was entered with the following: • Bladder cancer • Lung cancer • Cardiovascular disease • Myocardial infarction • Spermatogenesis • Low back pain • Musculoskeletal disorder • Kidney • Renal cancer • Hypertension Each of the search terms—work hours, shift work, sleep schedule—was entered with the following: • Gastrointestinal • Diabetes • Glycemic control • Lipid • Cholesterol • Obesity • Mental health • Depression • Peripheral neuropathy • Neurologic disorder • Reproductive • Fertility • Spontaneous abortion • Musculoskeletal disorders In addition, the following was searched: • Swing shift work and health • Rotating shift and health • Sleep cycle and health SELECTION CRITERIA Primary Sources The initial search resulted in more than 1,850 articles. When deemed appropriate by title, the abstracts were reviewed for relevance to the topics of CMV operator health and the health effects of work hours, shift work, and sleep schedule. The preliminary list included 139 abstracts. Those not pertaining to duration of work shift, duration of driving, working periods that shift over a 24-hr day, duration of sleep more than 6 hr, and effects of cumulative driving, were then removed from the list. This left approximately 70 articles. Fifteen were not avail- able either because they were published in foreign languages without translation or they were not found in the periodical section of the University of Illinois at Chicago’s Health Sci- ences Library. They were not judged to provide unique infor- mation for the analysis, were not translated, and no further efforts were made to obtain them. The remaining 55 articles were reviewed. Twenty-five were chosen and summarized by a primary reviewer to be included in the synthesis based on the validity of the methodology, the relevance of the studied population to truck driving and the quality of the statistical analysis of health outcomes. These were abstracted and evaluated according to the form provided by FMCSA to highlight the relevance to this review. The assessments of these articles and of the conclusions as to their meaning for the report are the product of the primary reviewers. The summaries focused specifically on the effects of extend- ing driving time from 10 to 11 hr per day and extending the total hours worked per week provided for in the new regula- tions. They focused as well on the effects of disrupting cir- cadian rhythm through swing swifts and of sleeping not more than 6 hr—conditions potentially relieved by the new regu- lations. The health effects of exposure to carcinogens and noise are cumulative so articles pertaining to long-term expo- sure, not just hours per day or week, were included in the can- cer and hearing loss summaries. Secondary Sources Articles pertaining to causality alone, for example, the link between diesel exhaust and lung cancer, are included in the

10 bus and tramway drivers in Copenhagen, a negative associ- ation between lung cancer and increased years of employment was found (Soll-Johanning 2003). Finally, a meta-analysis of 29 studies addressing occupational exposure to diesel exhaust and lung cancer showed that 21 of the 23 studies meeting the inclusion criteria observed relative risk estimates greater than one. A positive duration response was noted in all studies quantifying exposure (Bhatia 1998). Several additional articles showing an association between exposure to diesel exhaust and lung cancer were found and listed in the secondary references. Three articles on lung can- cer referenced in the notice of proposed rulemaking draft of December 17, 2004, as sent to Office of Management and Bud- get, are not included here because they did not address HOS or cumulative exposure; they were surveillance/prevalence studies. Bladder Cancer Several articles indicating an association between truck driving and bladder cancer were found. The most recent arti- cle was selected for summary. The others can be found in the secondary references. Three articles addressed the association between duration of exposure to diesel exhaust and bladder cancer. A popula- tion based case-control study in New Hampshire found a pos- itive association between bladder cancer and tractor-trailer driving as well as a positive trend with duration of employ- ment (Colt 2004). A large retrospective cohort in Finland found increased standard incidence ratios for 6 types of can- cer in truck drivers. Cumulative exposure to diesel exhaust was negatively associated with all cancers except ovarian cancer in women with high cumulative exposure (Guo 2004). A meta-analysis of 29 studies on bladder cancer and truck driv- ing found an overall significant association between high exposure to diesel exhaust and bladder cancer as well as a dose- response trend. The authors concluded that diesel exhaust exposure may result in bladder cancer, but the effects of mis- classification, publication bias, and confounding could not be fully taken into account (Boffetta Jan. 2001). WBV Effects As to objective findings of vertebral pathology, Heliovaara reported in 1987 on a case-control study of patients followed for 11 years after completing a normal physical exam. Those discharged from a hospital with the diagnosis of herniated lumbar intervertebral disc or sciatica were compared with 4 controls each. In men, the risk of being hospitalized due to herniated lumbar disc or sciatica was lowest in professional and related occupations, significantly higher in all other groups, and highest in blue-collar workers in industry and motor vehicle drivers. The variation in the risk between occu- pational groups of women proved less but was nevertheless secondary references because these new regulations do not change this factor. The National Institute for Occupational Safety and Health (NIOSH) document of April 2004, Overtime and Extended Work Shifts: Recent Findings on Illnesses, Injuries, and Health Behaviors, is not included in this review. This document reviewed the literature and was consistent with this review but did not add any new insight to the articles already gath- ered on those issues. REVIEW OF PRIMARY SOURCES The summaries are divided into the following subsections cardiovascular disease, lung cancer, bladder cancer, WBV effects, musculoskeletal disorders, GI disorders, noise-induced hearing loss, reproductive effects, effects of long work hours, effects of disruption of circadian rhythm, and effects of length of sleep. Cardiovascular Disease Two articles addressed the issue of hours of work and dura- tion of exposure. A case-control study of the risk of myocar- dial infarction (MI) from exposure to motor exhaust found a positive association, although results were not significant (Gustavsson Mar 2001). A case-control study of the risk of MI from long working hours found a U-shaped relationship with mean working hours of ≥11 hr compared with working 9 to 11 hr with a trend toward increasing risk with increasing hours (Sokejima 1998). Numerous articles were found on the association of cardio- vascular disease and professional driving. These are included in the secondary references. Lung Cancer There are numerous articles reporting on an association between lung cancer and work in occupations where there is exposure to diesel exhaust and other combustion particles. Diesel exhaust is considered to be a probable lung carcino- gen by the U.S. EPA, the World Health Organization, and U.S. Department of Health and Human Services National Toxicology Program. In this review, four articles addressed the issue of hours of work and duration of exposure. A large case-control study in Germany found a significant association between lung cancer and employment as a profes- sional driver, as well as evidence of a dose-response relation- ship by years of exposure to diesel exhaust (Bruske-Hohlfeld 1999). An exposure-response analysis and risk assessment of lung cancer and diesel exhaust found a significant increase in lung cancer risk with increasing estimated cumulative expo- sure to diesel exhaust among workers in the trucking indus- try based on an historical extrapolation of elemental carbon levels (Steenland Sept 1998). In a large case-control study of

still apparent. In contrast, a Finnish case-controlled study of monozygotic twins published in 2002 did not find any sig- nificant differences in vertebral degeneration between drivers and nondrivers over thousands of hours of estimated driving time (Battie 2002). A study of Danish professional drivers in 1996 found that almost all men in occupations involving professional driving had statistically significant elevated risks of being hospital- ized with prolapsed cervical intervertebral disc (Jensen 1996). This information was secured by following all economically active men in Denmark, identified on January 1, 1981, and fol- lowed for first hospitalization with prolapsed cervical inter- vertebral disc until December 31, 1990. Finally, based on these and other studies, a review done for the British Columbia Workers’ Compensation Board in 1999 concluded that “The data support a causal link between back disorders and both driving occupations and whole body vibra- tion” (Teschke 1999). Musculoskeletal Disorders Studies addressing musculoskeletal disorders in truck driv- ers by and large evaluate the effects of WBV and are included in that section. A questionnaire survey of Japanese truck drivers found short resting time and irregular duty time to be significant risk factors for LBP. It also found positive but insignificant associations with long driving time in a day and in a week but the hours were not quantified (Miyamoto 2000). A study of knee pain in taxi drivers found a significantly increased risk of knee pain in workers with >10 hr of daily driving. A sig- nificant dose-response trend was also seen (Chen April 2004). GI Disorders A questionnaire study of auto workers in the Midwest found that schedule variability, evening shift, and number of hours worked per week were significantly associated with adverse GI outcomes (Caruso Dec. 2004). Noise-Induced Hearing Loss The American College of Occupational and Environmen- tal Medicine in its 2002 statement on noise-induced hearing loss noted the following: . . . the risk of noise-induced hearing loss is considered to increase significantly with chronic exposures above 85 dBA for an 8-hr time-weighted average (TWA). In general, con- tinuous noise exposure over the years is more damaging than interrupted exposure to noise which permits the ear to have a rest period. The Occupational Safety and Health Administration (OSHA) noise exposure standard for the workplace for unpro- 11 tected ears is 90 dBA limited to 8 hr per day. FMCSA has adopted a 90 dBA noise standard. In 1995, the Office of Motor Carriers conducted a study of noise in CMVs (Robinson et al. 1997). The results of this study showed that noise levels in CMV cabs as reported over the last 25 years (1970 to 1995) have decreased. Other envi- ronmental studies confirm that overall cab noise levels have declined over this period as documented by several studies and reported in Robinson (1997). This study found that the overall broadband sound pressure level for the nine trucks evaluated was 89.1 dBA for eight conditions of highway driving. The truck-cab average of 89.1 dBA was very close to the FMCSA permissible exposure limit of 90 dBA based on the OSHA 8-hr day TWA standard. This study measured the noise exposure of 10 truck drivers during normal commercial runs of 8 to 18 hr. The noise was measured with rest breaks, meal breaks, and refueling breaks included, so they represented realistic projections of actual driver exposure. In a more recent study of a variety of models, makes, and age of tractors as well as routes that covered different types of Canadian terrain, noise exposure was measured (more than 400 measurements) under several conditions. The noise level recorded ranged from 78 to 89 dBA, with a mean of 82.7 dBA. Trucks with cabs mounted over the engine were quieter than other trucks by about 2.6 dBA. When the radio was on and the side window open the levels were regularly 85 dBA and in 10% of the cases above 90 dBA (Seshagiri 1998). Reproductive Effects Two studies were reviewed that addressed years of driving and male reproductive function. Because this exposure dura- tion does not relate to daily or weekly driving hours, these articles are secondary references. Effects of Long Work Hours In a study on employees from 45 companies in the Nether- lands, need for recovery scores (subjective measure of the self-perceived need to rest) were significantly elevated in those working 9 to 10 hr per day, >40 hr per week with fre- quent overtime (Jansen 2003). A literature review of recent empirical research on extended work hours and health con- firms findings from studies on cardiovascular diseases, ill- nesses leading to disability retirement, and subjectively reported ill health (van der Hulst 2003). A review document published by NIOSH in April 2004 titled “Overtime and Extended Work Shifts: Recent Findings on Illnesses, Injuries, and Health Behaviors” (Publication No. 2004-143), documents the lack of data on general health effects and even when looking at fatigue and accidents iden- tifying “differences between 8-hr and 12-hr shifts are difficult because of the inconsistencies in the types of work schedules examined across studies. Work schedules differed by the time

of day (i.e., day, evening, night), fixed versus rotating sched- ules, speed of rotation, direction of rotation, number of hours worked per week, number of consecutive days worked, num- ber of rest days, and number of weekends off.” Effects of Disruption of Circadian Rhythm Two studies using experimental conditions to evaluate the effect of circadian rhythm disruption on insulin secretion found increased insulin resistance and glucose response asso- ciated with a longer sleep-wake cycle such as that which might be found with rotating shift work (Morgan 1998). Two-hundred sixty-one shift workers completed the stan- dard shift work index in an investigation of health and well- being (Barton 1994). Workers on an advancing system were more likely to complain of digestive and cardiovascular (CV) disorders then those on a delayed rotating system. Authors con- cluded that the combination of direction of rotation and length of break when changing from one shift to another may be a crit- ical factor in the health and well-being of shift workers. 12 In a thorough review of the literature on shift work and health up to 1999 appearing as a chapter in a hardbound text (Scott 2000), the author concludes that GI, cardiovascular disease, and reproductive dysfunctions are more common in shift workers and that these effects may be due to shift work factors such as rotating or fixed shifts, number of nights worked consecutively, predictability of schedule, and length of shift and starting time. Exacerbation of medical conditions such as diabetes, epilepsy, psychiatric disorders as well as the diseases noted above may occur due to sleep deprivation and circadian rhythm disruption. Effects of Length of Sleep No articles were found that demonstrated a clear health impact of increasing sleep time during the work week from 6 hr (reflecting the sleep time that could occur with 8 hr off work allowing for travel time) to 8 hr (reflecting the sleep time that could occur under the new regulations with 10 hr off work).

13 Susan Buchanan Bruske-Hohlfeld, I., Mohner, M., Ahrens, W., Pohlabeln, H., Heinrich, J., Kreuzer, M., Jockel, K.H., and Wichmann, H.E. “Lung cancer risk in male workers occupationally exposed to diesel motor emissions in Germany.“ Am J Ind Med. 1999 Oct;36(4):405–14. Background: Although in several epidemiological studies exposure to diesel motor emis- sions (DME) shows an elevated lung cancer risk, it is still controversial whether DME is a human carcinogen. Methods: In a pooled analysis of two case-control studies on lung can- cer in Germany a total of 3,498 male cases with histologically or cytologically ascertained lung cancer and 3,541 male population controls were included. Information about lifelong occupational and smoking history was obtained by questionnaire. Drivers of lorries, buses, taxies, diesel locomotives and forklift trucks, bulldozers, graders, excavators, and tractors, were considered as exposed to DME and their cumulative exposure was estimated. All odds ratios were adjusted for smoking and asbestos exposure. Results: The evaluation of lung cancer risk for all jobs with DME-exposure combined showed an odds ratio of OR = 1.43 (95%-CI: 1.23–1.67). Most pronounced was the increase in lung cancer risk in heavy equip- ment operators (OR = 2.31 95%-CI: 1.44–3.70). The risk of tractor drivers increased with length of employment and reached statistical significance for exposures longer than 30 years (OR = 6.81, 95%-CI: 1.17–39.51). The group of professional drivers (e.g., trucks, buses, and taxies), showed an increased risk only in West Germany (OR = 1.44, 95%-CI: 1. 18–1.76), but not in East Germany (OR = 0.83, 95%-CI: 0.60–1.14). DME-exposure in other traffic-related jobs (e.g., diesel engine locomotive drivers, switchmen, forklift opera- tors) was associated with an odds ratio of OR = 1.53 (95%-CI: 1.04–2.24). Conclusions: The study provides further evidence that occupational exposure to diesel motor emissions is associated with an increased lung cancer risk. Two case-control studies were pooled for a joint analysis: all patients born in Germany after 1913 and diagnosed with lung cancer between 1988 and 1993 were used in one of the stud- ies. The other study evaluated residents in 4 regions of Germany who were diagnosed with lung cancer in 1994. Controls for both studies were selected at random from municipal reg- istries. A standardized questionnaire was performed in face-to-face interviews to obtain demographic information and job histories. Exposure to diesel motor exhaust was charac- terized by years of exposure after evaluating job task descriptions. Lung cancer risk was calculated according to the cumulated exposure and with respect to job group. To estimate lung cancer risk in workers occupationally exposed to diesel motor exhaust. 3,498 cases and 3,541 controls Professional drivers Exposure was estimated based on participants’ self-reported job task history. Working Conditions (Environmental except sleeper berth) Odds ratios were adjusted for smoking and asbestos exposure and showed that professional drivers had significantly higher rates of lung cancer. Workers of any category who were exposed to diesel motor exhaust for between 20 and 30 years had significantly higher rates of lung cancer. Risk increased with increased duration of exposure. And compared with workers who had never been exposed, those who were exposed had a 43% higher rate of lung cancer. ARTICLE SUMMARIES* Reviewer: Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references): *Summaries are presented in the order submitted by the researchers.

“Our study results show an increasing lung cancer risk for professional drivers, adjusted for smoking and asbestos exposure (Table III), which is similar to the results of most other epi- demiological studies.” (p. 412) Though retrospective with estimated exposures, this study, with a large sample population, showed significant associations between lung cancer and both exposure to diesel exhaust and a dose-response. 14 Reviewer’s Notes:

15 Susan Buchanan Colt, J.S., Baris, D., Stewart, P., Schned, A.R., Heaney, J.A., Mott, L.A., Silverman, D., and Karagas, M. “Occupation and bladder cancer risk in a population-based case-control study in New Hampshire.” Cancer Causes Control. 2004 Oct;15(8):759–69. Objective: To identify occupations with excess bladder cancer risk in New Hampshire, where bladder cancer mortality rates have been elevated for decades. Methods: Lifetime occupational histories were obtained from interviews with 424 cases and 645 controls in a population-based case-control study. Unconditional logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI) for each occupation, adjusted for age and smoking. Analyses by duration of employment were carried out and interactions with smoking were examined. Results: Male tractor-trailer truck drivers had an elevated risk for bladder cancer (OR = 2.4, CI = 1.4–4.1), with a significant positive trend in risk with increasing duration of employment (P (trend) = 0.0003). Male metal/plastic pro- cessing machine operators also had a significant excess (OR = 4.9, CI = 1.6–15.1), attrib- utable mainly to molding/casting machine operators (OR = 16.6, CI = 2.1–131). Elevated risk was also observed for male fabricators, assemblers, and hand workers (OR = 1.8, CI = 1.0–3.4). Women in certain sales occupations (sales clerks, counter clerks, and cashiers) had a significant excess risk (OR = 2.2, CI = 1.3–3.9) and a significant trend with duration of employment (P (trend) = 0.016), as did female health service workers (OR = 4.1, CI = 1.6–10.7; P (trend) = 0.014). There was a positive interaction between smoking and employment as a health service worker (p = 0.036). Conclusions: These findings are gen- erally consistent with previous studies. Elevated risks for male molding/casting machine operators, female sales workers, and female health service workers, especially those with a history of smoking, require further investigation. This study is part of a larger population-based case-control study evaluating risk factors for bladder cancer in New Hampshire. This paper reports on the occupational data. New Hamp- shire residents diagnosed with bladder cancer between July 1994 and June 1998 were iden- tified from the state cancer registry. Controls were selected from the Department of Trans- portation population lists and matched for age and gender. Participants underwent a detailed in-home interview and information on job history was collected. Odds ratios were calcu- lated adjusting for age and smoking status. To identify high-risk occupations in New Hampshire, where bladder cancer mortality rates have been elevated for decades, and to re-examine occupations that have been found to be associated with bladder cancer in previous studies. 424 cases, 645 controls Tractor-trailer truck drivers This study excludes cases which did not survive to the time of the interview, such as those with rapidly growing or late diagnosed cancers (e.g., most severe cases). This would be a positive bias if another factor produced a more aggressive picture than driving exposure and a negative bias if the reverse was true. Exposure duration had only 2 categories: employed as truck driver <5 years or ≥5 years. Driver Health (General) Tractor-trailer truck drivers had an excess bladder cancer odds ratio of 2.3, which was sig- nificant. See Table 2. There was a positive trend of increasing risk with duration of employ- ment. See Table 3. Duration of employment was categorized by <5 year or ≥5 years. “In Reviewer: Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references):

our study, bladder cancer risk was higher among men who drove trucks typically fueled by diesel (tractor-trailers) than among drivers of other types of trucks, and there was no increase for taxicab or bus drivers. Thus, our study supports the possibility of diesel expo- sure as the putative factor.” (p. 765) This study was chosen from several that have shown significant odds ratios for bladder can- cer in truck drivers (see secondary references). Although the characterization of exposure was limited, it was the most recent study published on this issue. It showed both a positive association between truck driving and bladder cancer and a dose-response trend between drivers exposed ≥5 years compared with those with exposure for <5 years. 16 Reviewer’s Notes:

17 Susan Buchanan Guo, J., Kauppinen, T., Kyyronen, P., Heikkila, P., Lindbohm, M.L., and Pukkala, E. “Risk of esophageal, ovarian, testicular, kidney and bladder cancers and leukemia among Finnish work- ers exposed to diesel or gasoline engine exhaust.” Int J Cancer. 2004 Aug 20;111(2):286–92. Occupational exposure to diesel exhaust has been classified as probably carcinogenic and occupational exposure to gasoline engine exhaust as possibly carcinogenic to humans. Ear- lier results concerning cancers other than lung cancer are scarce and inconsistent, and exposure-response relations have seldom been reported. We followed up a cohort of all eco- nomically active Finns born between 1906 and 1945 for 30 million person-years during 1971–1995. Incident cases of esophageal cancer (n = 2,198), ovarian cancer (5,082), testicu- lar cancer (387), kidney cancer (7,366), bladder cancer (8,110) and leukemia (4,562) were identified through a record linkage with the Finnish Cancer Registry. Occupations from the population census in 1970 were converted to exposures to diesel and gasoline engine exhausts with a job-exposure matrix (FINJEM). Cumulative exposure (CE) was calculated as product of prevalence, level and estimated duration of exposure. The relative risk of cancer for expo- sure categories in relation to the unexposed group was calculated using the Poisson regres- sion model and adjusted for confounders. An increasing relative risk for ovarian cancer was observed with the increasing CE of diesel exhaust (p for trend = 0.006). The relative risk in the highest CE category was 3.69 (95% CI = 1.38–9.86). For gasoline engine exhaust, the rel- ative risk was significantly increased only in the middle CE category (1.70; 95% CI = 1.11–2.62). Slight elevations of relative risk for bladder and kidney cancers were found at the lowest exposure level of engine exhausts, largely attributable to drivers. No effect of the expo- sures was observed for the other cancers. This study suggests an exposure-response relation between diesel exhaust and ovarian cancer. Copyright 2004 Wiley-Liss, Inc. The study cohort comprised all economically active Finns born between 1906 and 1945. The incident cases of esophageal cancer, ovarian cancer, testicular cancer, kidney cancer, bladder cancer, and leukemia, diagnosed between 1971 and 1995 among persons born between 1906 and 1945 were extracted from the Finnish Cancer Registry. A job-exposure matrix was created on the basis of the census occupation and a national job-exposure matrix (FINJEM). The exposure estimates were based on exposure measurements, hazard surveys, and the judgments of 20 Finnish occupational hygienists. Since the exposure to diesel exhaust decreased in most occupations between 1945 and 1984, cumulative exposure was estimated for 5-year birth cohorts. Cumulative exposure to diesel exhaust was categorized into three categories: lowest, middle, and highest, in mg/m3-years. Risk ratios were con- trolled for cancer-specific confounding factors: socioeconomic status, cigarette smoking, alcohol consumption, body mass index (BMI), number of children (for women), and occu- pational exposure to ionizing radiation and aromatic hydrocarbon solvents. To assess the risk of leukemia and cancers of the esophagus, ovary, testis, kidney and blad- der suspected to be associated with engine exhausts. 2,198 cases of esophageal cancer, 5,082 cases of ovarian cancer, 387 cases of testicular can- cer, 7,366 cases of kidney cancer, 8,110 cases of bladder cancer, and 4,562 cases of leukemia Truck drivers; no further characterization Exposure data not specific to individual cases Driver Health (General) Standard incidence ratios of all six types of cancer in truck drivers were all greater than 1.0 and leukemia was statistically significant (Table II). Relative risks for cancers in occupations Primary Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references):

exposed to high, middle, or low levels of engine exhaust were significant for high cumula- tive exposure to diesel exhaust and ovarian cancer (Table III). Relative risks for high or mid- dle cumulative exposures were all insignificant for esophageal cancer, testicular cancer and leukemia. Kidney and bladder cancer were associated with low exposures. “Applying more sophisticated analysis to the same data, the present study revealed a positive exposure- response relation between ovarian cancer and diesel exhaust.” (p. 290) “In the present study, we did not observe any positive exposure-response relations between engine exhausts and the other 5 cancers.” (p. 290) This study addresses general causality as well as dose-response. Relative risks for all six types of cancer were greater than 1. Regarding dose-response, this was a negative study except for the interesting association between ovarian cancer and high cumulative exposure to diesel exhaust. 18 Reviewer’s Notes:

19 Susan Buchanan Jansen, N., Kant, I., van Amelsvoort, L., Nijhuis, F., and van den Brandt, P. “Need for recovery from work: evaluating short-term effects of working hours, patterns and sched- ules.” Ergonomics. 2003 Jun 10;46(7):664–80. In this paper working hours, patterns, and work schedules of employees were evaluated in terms of need for recovery from work. Self-administered questionnaire data from employ- ees of the Maastricht Cohort Study on Fatigue at Work (n = 12,095) were used. Poisson regression analyses and multivariate logistic regression analyses revealed that higher work- ing hours a day and working hours a week generally went together with more need for recovery from work. Overtime work was associated with higher need for recovery from work in both genders. Both male and female three-shift or irregular shift workers had higher odds of elevated need for recovery compared with day workers. When additionally control- ling for work-related factors, need for recovery levels among shift workers substantially low- ered. This study clearly showed that working hours and schedules are associated with need for recovery from work, with different associations for men and women. The associations between work schedules and need for recovery from work were very interrelated with other work-related factors. Future studies could further investigate the possibility that (a) shift work might function as a proxy of other work-related factors that explain the different lev- els in need for recovery from work or (b) job demands are perceived higher among shift workers and may therefore lead to more need for recovery from work. Data from a baseline questionnaire from a large study on fatigue at work was used. Partic- ipants were employees of 45 different companies in The Netherlands. Three populations were studied: A. day employees only, B. day workers with vocation-level education only, and C. workers with 26 to 35 hr/wk of work, which would include those working on 5-shift systems. The Need for Recovery scale used was derived from the Dutch Experience and Assessment of Work questionnaire. The scale was derived using statements such as “I find it hard to relax at the end of a working day” and “My job causes me to feel rather exhausted at the end of a working day.” The present study was designed to describe the magnitude of associations between work- ing hours and need for recovery from work. Population A: 5170, Population B: 2167, Population C: 815 n/a No information on occupation. Healthy worker effect might be seen in workers who choose to work shifts. This would underestimate the effect. Recovery/Restart Periods In men, continuous Need for Recovery scores were significantly associated with working more than 40 hr per week compared with fewer hours per week, working 9 to 10 hr per day compared with working fewer hours per day, and working overtime frequently. Working ≤25 hr per week was also significant. These results were controlled for age, disease, job characteristics of physical, emotional, and psychological demands. Using dichotomous out- come for Need for Recovery (highest quartile vs. lowest quartile), results in men showed significant associations between high need for recovery and working 9 to 10 hr per day, working more than 40 hr per week, and working frequent overtime. No dose-response analyses were performed. Regarding shift work, three-shift workers were significantly more likely to need recovery time from work than day workers. Reviewer: CompleteTitle: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references):

Author’s conclusion: “The study showed that high working hours a day and high working hours a week generally went together with a higher need for recovery, confirming our hypothesis that day workers with many working hours a week report more need for recov- ery from work compared to employees working less hours a week. Extension of the work- ing day, in terms of overtime work, was particularly associated with more need for recov- ery in both men and women.” (p. 674) This study, with a large sample, showed significant need for recovery from work in those working 9 to 10 hr a day, more than 40 hr per week, and overtime. 20 Reviewer’s Notes:

21 Susan Buchanan Miyamoto, M., Shirai, Y., Nakayama, Y., Gembun, Y., and Kaneda, K. “An epidemio- logic study of occupational low back pain in truck drivers.” J Nippon Med Sch. 2000 Jun;67(3):186–90. The factors involved in occupational LBP occurring in professional drivers were investi- gated epidemiologically with questionnaires (92 items) including LBP symptoms, personal factors and occupational factors. The responses of 153 of 181 truck drivers who work in a large chemical industry corporation were analyzed after they had completely filled in ques- tionnaires. As analysis of the results shows, the prevalence of LBP in 1 month of the sur- vey was 50.3%. Correlating among data of personal factors and LBP, the prevalence of LBP was significantly higher in the drivers (odds ratio of 2.7) who answered “yes” to the item “shortage of spending time with family” than in the drivers who did not answer yes. The occupational factors, working load and working environment showed no correlation with the prevalence of LBP. In contrast, 3 items of the working format related significantly to the prevalence of LBP: irregular duty time (odds ratio of 3.0), short resting time (2.4), and long driving time in a day (2.0). Eighty-one of the 153 drivers (52.9%) pointed out the rela- tionship between LBP and work, especially work which involves vibration or road shock. Our results and the results from previously published studies suggested that vibration is an obvious risk factor for LBP. From the viewpoint of prophylaxis, an improvement in work- ing conditions reduces the incidence of drivers’ LBP to some extent. Truck drivers who work for a large chemical industry corporation completed questionnaires. The questionnaire had 92 items with sections on LBP symptoms, personal factors, and occu- pational factors including working load, working environment, and working format. To investigate by use of questionnaires, the prevalence of LBP symptoms and its risk fac- tors among truck drivers. 153 completed questionnaires Truck drivers, no further characterization No information on participant recruitment. Were they volunteers who might be more likely to have symptoms? No information was given on job types or exposures of participants. They all worked for the same company so one might not be able to generalize these results. Details on risk factors were lacking: what do irregular duty time and short resting time mean exactly? Self-reported symptoms of back pain may not indicate medical condition. Driver Health (General) Lack of sleeping time was a risk factor for LBP but was not significant. Working load and working environment factors were not significant, although some associations were posi- tive. Two working format factors were significant: irregular duty time and short resting time. Insignificant but positive working format factors were long driving time in a day, long driving time in a week, long working time in a day, irregular meal time, and long working time in a week. (See Table 4, p. 189.) Despite the limitations noted above, this was a decent sized sample showing a significant relationship between LBP and irregular duty time and short resting time. Several other working format factors showed positive associations but were not significant. Overall this study suggests a relationship between driving hours in a day and LBP. Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references): Reviewer’s Notes:

Susan Buchanan Magnusson, M.L., Pope, M.H., Wilder, D.G., and Areskoug, B. “Are occupational drivers at an increased risk for developing musculoskeletal disorders?” Spine. 1996 Mar 15;21(6):710–7. Study Design: This study analyzed the role of exposure to driving and other covariates in reports of back, neck, and shoulder pain and resultant disability. Cohorts in Sweden and the United States were compared. Objectives: To establish the effect of mechanical and psy- chosocial factors in reporting back, neck, and shoulder pain and work loss. Summary of Background Data: There are numerous reports of a positive relationship between back pain and driving. However, exposure data are minimal. The influence of job satisfaction has not been assessed. Methods: The physical factors affecting reports of back, neck, and shoulder pain were investigated in a two-country cohort study of bus and truck drivers and sedentary workers. Vibration exposure was obtained by directly measuring the vibration imposed on the driver during a typical work day. Lifting exposure was attained by questionnaire. Cumu- lative exposure was computed based on work history. Musculoskeletal health information was based on a modified Nordic questionnaire, and other questionnaires recorded the phys- ical and psychosocial aspects of the work environment. Results: Of the sample, 50% reported LBP, with no difference between countries. The highest risk factors (odds ratios) for back and neck pain were long-term vibration exposure, heavy lifting, and frequent lift- ing. A combination of long-term vibration exposure and frequent lifting carried the highest risk of LBP. Work loss from LBP was influenced by perceived job stress. Conclusions: Vibration (resulting from driving) and lifting cause back, neck, and shoulder pain, whereas inability to work seems affected by stress at work. Participants were recruited by personal contact with workers in several companies in Ver- mont and in Gothenburg, Sweden, who were male truck drivers or bus drivers. Sedentary workers served as the control group. Musculoskeletal health information was based on modified Nordic questionnaires (a standardized questionnaire used to assess musculo- skeletal symptoms.) Another questionnaire had detailed questions about the work environ- ment and the amount of lifting, sitting, standing, and driving on the job. Vibration levels during representative driving conditions were measured. The summed products of “aver- age acceleration” × “exposure duration” represented the daily vibration dose for that driver. Long-term vibration exposure was calculated as the product of daily exposure dose and years on the job as drivers. To compare the effect of exposure to vibration on drivers’ back, neck, and shoulder pain with those of control subjects in cohorts in two countries. U.S.: 124, Sweden: 241 Bus drivers and truck drivers; no further detail given Did not explain recruitment nor any detail on the participants. Did not measure awkward postures and seated exposure. Working Conditions (Environmental except sleeper berth) “American truck drivers had a significantly higher daily exposure (to vibration) than bus drivers.” (p. 9 of 16) “Those who reported LBP had a significantly higher total long-term vibration exposure than those who did not report LBP in those aged 35 to 45 years. Long- term exposure to vibration (equal to the vibration exposure over years in the profession) 22 Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references):

23 was the strongest predictor of length of sick leave because of LBP.” (p. 9-10 of 16) “Sig- nificant single risk factors were . . . long-term vibration exposure.” (p. 11 of 16) Because this study did not elaborate on sampling and recruiting methods, it is difficult to judge its validity; however, results show that long-term exposure to vibration was a signif- icant risk factor for LBP. Reviewer’s Notes:

Susan Buchanan Sokejima, S. and Kagamimori, S. “Working hours as a risk factor for acute myocardial infarction in Japan: case-control study.” BMJ. 1998 Sep 19;317(7161):775–80. Objective: To clarify the extent to which working hours affect the risk of acute MI, inde- pendent of established risk factors and occupational conditions. Design: Case-control study. Setting: University and general hospitals and routine medical examinations at workplaces in Japan. Subjects: Cases were 195 men aged 30 to 69 years admitted to hospital with acute MI during 1990 to 1993. Controls were 331 men matched at group level for age and occu- pation who were judged to be free of coronary heart diseases at routine medical examina- tions in the workplace. Main Outcome Measures: Odds ratios for MI in relation to previous mean daily working hours in a month and changes in mean working hours during previous year. Results: Compared with men with mean working hours of >7 to 9 hr, the odds ratio of acute MI (adjusted for age and occupation) for men with working hours of >11 hr was 2.44 (95% CI 1.26–4.73) and for men with working hours of ≥7 hr was 3.07 (1.77–5.32). Compared with men who experienced an increase of ≤1 hour in mean working hours, the adjusted odds ratio of MI for men who experienced an increase of >3 hr was 2.53 (1.34–4.77). No appreciable change was observed when odds ratios were adjusted for established and psychosocial risk factors for MI. Conclusion: There was a U-shaped relationship between the mean working hours and the risk of acute MI. There also seemed to be a trend for the risk of infarction to increase with greater increases in mean working hours. Case-control study (in Japan) of male patients with first MI, recruited from four hospitals. Controls were matched by occupation and recruited at their mandatory yearly workplace physical. Questionnaires were completed on working hours. Odds ratios for MI were adjusted for smoking, hypertension, DM, BMI, and hypercholesterolemia. To clarify the extent to which working hours affect the risk of acute MI. 195 cases, 331 controls “Transport and Communications” was one of the occupational categories. Those who survived MI were interviewed. Those not surviving were excluded (history of work hours was not taken from surviving family members). Time on Task For the month before the MI, mean working day of ≥11 hr and a short working day (≤7 hr) were associated with a significantly increased risk of infarction compared with working 7 to 9 hr. (Table 3) When looking at the amount of increase in hours between the shortest amount of time worked in a month (in the previous year) compared with the month before the infarction, “there was a significant trend in the odds ratios increasing with greater increase in mean working hours.” (p. 778) Authors’ conclusion: “there seemed to be a trend for the risk of acute MI to increase with greater increases in working hours.” (p. 779) There was a significant increase in risk of MI with mean daily working hours of ≥11 hr. There was no increased risk for working 9 to 11 hr. The increase in odds ratio with increased CHANGE in mean working hours from shortest month to the month before MI may indi- cate that changes in the circadian rhythm may increase risk for MI. These results are not specific to truck drivers. 24 Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references): Reviewer’s Notes:

25 Susan Buchanan Seshagiri, B. “Occupational noise exposure of operators of heavy trucks.“ Am Ind Hyg Assoc J. 1998 Mar;59(3):205–13. More than 400 measurements were taken across Canada to assess the noise exposure of truck operators. The exposure of the driver was evaluated using both 3-dB (Leq) and 5-dB (L5dB) exchange rates. Driving with windows closed and radio not operating resulted in the lowest exposure. The drivers’ Leq ranged from 78 to 89 dBA, with a mean of 82.7 dBA; operating the radio increased the mean by 2.8 dB; driving with the driver’s side window open increased the mean exposure by 1.3 dB; and driving with the window open and oper- ating the radio resulted in an increase of 3.9 dB. Trucks with cabs mounted over the engine appeared to be quieter than standard trucks by about 2.6 dB. Operations on four-lane high- ways were 1.6 dB noisier than on two-lane highways, most likely as a result of higher speeds on the former. Long haul (city-to-city) operations on hilly terrain appeared to be qui- eter than on flat terrain by about 2.2 dB, again probably indicating the strong effect of speed. Regression analysis was used to obtain relationships between a number of variables such as Leq and L5dB. These measurements indicate that the exposure of a driver is almost cer- tain to exceed the current threshold limit value for noise (85 dBA for 8 hr with a 3-dB exchange rate) when driving with the radio on and the driver’s side window open. Compa- rable numbers in terms of L5dB are also reported. Eight trucking companies in seven areas of Canada were included in a survey of a variety of models, makes, and ages of tractors as well as routes that covered different types of ter- rain. Tests were conduced under four conditions: (1) all windows and vents closed, radio and CB not operating, (2) all windows and vents closed, radio operating, CB operating or not operating, (3) driver’s side window open, radio and CB not operating, (4) driver’s side window open, radio operating, CB operating or not operating. To evaluate the noise exposure of truck drivers under normal operating conditions. 135 long-haul samples, 66 pick-up and delivery samples, and 29 sleeper berth samples Long-haul drivers n/a Working Conditions (Environmental except sleeper berth) Personal samples showed that driving with the radio on and the windows closed resulted in an Leq of 85.5 dBA. Driving with the window open and the radio on resulted in an Leq of 86.6 dBA. Ten percent of the long-haul drivers exceeded an Leq of 90 dBA while 53% exceeded 85 dBA. (The mean level of exposure was 85 dBA.) “It is clear from this analy- sis that truck drivers incur a significant risk to their hearing depending on the operating con- ditions, in particular whether they routinely drive with the window open, and use their radio and/or CB at a relatively high volume.” (p. 212) “The risk of hearing loss among drivers of extra-long duration trips is of concern.” (p. 213) This is a study performed specifically to determine whether the revised sound level limits for employees in Canada should apply to the trucking industry. Noise-induced hearing loss is determined by cumulative exposure, so this is an important study showing that truck driv- ers are likely exposed to damaging levels of noise. Additional hours on the job will affect the long-term hearing acuity of drivers. Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references): Reviewer’s Notes:

Peter Orris Robinson, G.S., Casali, J.G., Lee, S.E. Role of Driver Hearing in Commercial Motor Vehi- cle Operation: An Evaluation of the FHWA Hearing Requirement. FHWA Contract No. DTFH61-C-00172. The Federal Highway Administration (FHWA) currently requires that all interstate truck drivers have a certain minimal level of hearing in order to obtain a commercial driver’s license. A research program was undertaken to determine whether this hearing requirement is necessary, and if so, whether the requirement is set at the correct audiometric level. This was a multi-part project. The first segment of the project consisted of an extensive litera- ture review on the topics of CMV driving and hearing, the effects of occupational noise exposure, and truck-cab noise. Another extensive segment of the literature review con- cerned the effectiveness of the forced-whisper test, which is one of two methods by which the FHWA allows truck driver hearing to be tested. No firm conclusions could be reached on any of these topics based solely on the literature review, but several interesting research questions and needs were identified as a result thereof. The next phase of the research project was an extensive task analysis. This began with a review of truck driving task analysis literature, very little of which took into consideration the role of hearing or noise in the driving task. A classical task analysis was then performed, beginning with structured interviews with 11 subject matter experts (SMEs) for truck driving. The consensus of these SMEs was that hearing is required in order to drive a truck safely. The specific results of the SME interviews were then used to compile a task analysis questionnaire. The questionnaire itself was reviewed by several experts and verified by extensive job obser- vations of the truck driving task. The finalized questionnaire was distributed to 80 truck driv- ers, and the answers were used to compile a final list of hearing-critical truck driving tasks, as well as a list of mechanical problems which can be detected through the use of hearing. A further result of the questionnaire was a list of critical driving incidents involving hearing which had been experienced by drivers completing the questionnaires. To determine the noise level in truck cabs, spectral measurements were taken for nine trucks under eight different conditions during actual commercial runs. Measurements were also taken of engine idle noise and noise in the sleeper-berth. These were compared with other, previous measurements to determine whether truck-cab noise is increasing or decreasing with model-year changes. Although these measurements demonstrated a higher overall noise level than did several recent studies, this study was performed under more realistic conditions than the aforementioned studies. When compared with older studies of truck- cab noise (15 to 30 years ago), these measurements actually showed a decrease. So truck- cab noise has decreased over the last 30 years, but perhaps not by as much as had been reported in some recent studies that considered only ideal conditions. The overall broad- band sound pressure level (SPL) for these nine trucks was 89.1 dBA for eight conditions of highway speed driving. The sleeper-berth mean SPL was 81.6 dBA, while for the engine idle conditions, cab noise was 68.7 dBA. The highway-speed driving SPL of 89.1 dBA was very close to the OSHA permissible exposure limit of 90 dBA for an 8-hr day (although the trucking industry is not required to follow OSHA regulations). Dosimetry was used to measure the noise doses experienced by 10 truck drivers during nor- mal commercial runs of 8 to 18 hr. Doses were also measured for nine sleeper berths. Doses were calculated for 8-, 10-, and 24-hr periods for the truck cab, and for 5-, 10-, and 24-hr periods for the sleeper berth. The 10-hr doses for all trucks were less than 50% (the OSHA action level at which a hearing conservation program must be put into place in industry). When sleeper-berth doses were added in for 24-hr calculations, the doses exceeded the 50% level and approached the 100% level. These calculations mainly applied to team drivers, since they included sleeper-berth doses measured with the truck running at highway speeds. 26 Reviewer: Complete Title: Executive Summary

27 Single drivers who spent sleeping time in the sleeper berth with the engine idling or shut off did not experience excessive noise doses in contemporary cabs, since the engine idle SPL was significantly less than the highway speed SPL. Sleeper-berth doses were so much lower than cab doses that drivers were encouraged to spend as much non-driving time as possible in the sleeper berth with the curtains closed in order to reduce their total noise exposure. One important consideration for the dosimeter measurements is that they included rest breaks, meal breaks, and refueling stops as set by the driver. The doses were therefore representative of the doses drivers received on a day-to-day basis. In order to determine whether truck drivers experience a temporary decrement in hearing after a normal driving shift (known as temporary threshold shift or TTS), pre- and post- workday audiograms were performed for a group of 10 drivers. Results showed no such decrease, although there were two confounding factors which might account for the lack of TTS. First, due to scheduling constraints, drivers were not given advance notice of partic- ipation in the experiment, and thus were not informed to control their off-the-job noise exposure for 16 hr prior to the pre-work audiogram. Noise exposure during this critical time could have raised the threshold level for the pre-work audiogram, thus masking any TTS which might have occurred. Second, the post-work audiogram was given from 15 to 25 min after the end of the work shift due to driver availability and equipment warm-up time. A maximum delay of 2 min is preferred for laboratory TTS measurements, but delays of up to 25 min are not uncommon for field experiments such as this one. This delay could have allowed recovery from any TTS that actually occurred. Pre-work audiograms were avail- able for another group of 20 drivers, resulting in a 30-driver sample for investigation of noise-induced permanent threshold shift (NIPTS). These data were compared with thresh- old data for non-noise exposed males of the same mean age. This comparison showed sig- nificantly higher thresholds for these 30 drivers (as compared with the non-noise exposed population data) at 3000, 4000, and 6000 Hz, but not at 500, 1000, or 2000 Hz (the three frequencies required to be tested by the FHWA if the audiometric test is used). As a result of the prevalence of noisy hobbies and previous occupations among both this group of driv- ers and the group completing questionnaires, no conclusions could be reached as to whether the NIPTS was caused by truck-cab noise. To determine the noise level in truck cabs, spectral measurements were taken for nine trucks under eight different conditions during actual commercial runs. Measurements were also taken of engine idle noise and noise in the sleeper berth. These were compared with other, previous measurements to determine whether truck-cab noise was increasing or decreasing with model-year changes. Dosimetry was used to measure the noise doses experienced by 10 truck drivers during nor- mal commercial runs of 8 to 18 hr. Doses were also measured for nine sleeper berths. In order to determine whether truck drivers experience a temporary decrement in hearing after a normal driving shift (known as temporary threshold shift or TTS), pre- and post- workday audiograms were performed for a group of 10 drivers. Pre-work audiograms were available for another group of 20 drivers, resulting in a 30-driver sample for investigation of noise-induced permanent threshold shift (NIPTS). These data were compared with threshold data for non-noise exposed males of the same mean age. This research program was undertaken to determine whether the FHWA hearing require- ment is necessary, and if so, whether the requirement is set at the correct audiometric level. n/a Professional drivers Methodology: Scope of Work: Sample Size: Industry Sector:

Limited number of drivers and trucks tested Other Study Findings Measurements demonstrated a higher overall noise level than did several recent studies, this study was performed under more realistic conditions than the aforementioned studies. When compared with older studies of truck-cab noise (15 to 30 years ago), these measure- ments actually showed a decrease. So truck-cab noise has decreased over the last 30 years, but perhaps not by as much as had been reported in some recent studies that considered only ideal conditions. The overall broadband SPL for these nine trucks was 89.1 dBA for eight conditions of highway speed driving. The sleeper-berth mean SPL was 81.6 dBA, while for the engine idle conditions, cab noise was 68.7 dBA. The highway-speed driving SPL of 89.1 dBA was very close to the OSHA permissible exposure limit of 90 dBA for an 8-hr day (although the trucking industry is not required to follow OSHA regulations). The 10-hr doses for all trucks were less than 50% (the OSHA action level at which a hear- ing conservation program must be put into place in industry). When sleeper-berth doses were added in for 24-hr calculations, the doses exceeded the 50% level and approached the 100% level. Single drivers who spend sleeping time in the sleeper berth with the engine idling or shut off should not experience excessive noise doses in contemporary cabs, because the engine idle SPL is significantly less than the highway speed SPL. There were significantly higher thresholds for these 30 drivers (as compared with the non- noise exposed population data) at 3000, 4000, and 6000 Hz, but not at 500, 1000, or 2000 Hz (the three frequencies required to be tested by the FHWA if the audiometric test is used). As a result of the prevalence of noisy hobbies and previous occupations among both this group of drivers and the group completing questionnaires, no conclusions could be reached as to whether the NIPTS was caused by truck-cab noise. An excellent literature review and comprehensive small study. Cannot fully evaluate cur- rent exposure resulting from changing cab design. 28 Major Limitations: Findings Directly Related to HOS (include page references): Reviewer’s Notes:

29 Susan Buchanan Soll-Johanning, H., Bach, E., and Jensen, S.S. “Lung and bladder cancer among Danish urban bus drivers and tramway employees: a nested case-control study.” Occup Med (Lond). 2003 Feb;53(1):25–33. Background: The combustion of fossil fuels produces small amounts of mutagenic and car- cinogenic compounds. We investigated the association between employment and lung and bladder cancer in Danish bus drivers and tramway employees. Methods: We carried out a nested case-control study of 153 lung and 84 bladder cancer cases, and 606 controls sam- pled in a cohort of 18,174 bus drivers or tramway employees employed in Copenhagen dur- ing the period 1900 to 1994. The cases and controls or their next of kin were interviewed about smoking, along with occupational and residential history. An exposure index based on which bus routes the bus drivers had mainly been driving was established. Relative risks (RRs) were estimated by conditional logistic regression. Results: The analysis showed decreasing risk for lung cancer with increasing years of employment as a bus driver (RR = 0.97 for each added year, 95% CI = 0.96–0.99). The air pollution index based on main bus for the bus drivers showed no positive correlation with risk. All people ever employed by the Copenhagen Traffic Company between 1900 and 1994 were included. Data on date of start and end of work periods were linked with the Central Population Register. All lung and bladder cancer cases identified by the Danish Cancer reg- istry were contacted for a telephone interview. Cases were matched to 1 to 4 random con- trols from the original cohort based on year of birth. Exposure was characterized as “little diesel air pollution” before 1943, “moderate air pollution” from 1946 to 1958, and “sub- stantive air pollution” from 1958 onward. Bus routes for individual drivers were obtained for analysis by GIS. This information was used to create an exposure index. A previous retrospective cohort study performed in this group (see secondary references) found increased lung cancer risk with duration of employment in urban bus drivers or tramway workers but did not control for smoking. The current study used the same database and controlled for confounders such as smoking, place of residence, and working history. 18,174 bus drivers and tramway employees in original database. For this nested case-control study there were 153 lung cancer cases, 84 bladder cancer cases, and 606 controls. Bus drivers Exposures were estimated for urban work situations only. A substantial healthy worker effect would be expected in this design which would predispose to a negative result when evaluating association. Finally, the calculation of dose based on the assumption of an increasing intensity of exposure over a working lifetime might well produce a survivor effect mitigating or reversing a dose-response finding. Time on Task Increasing years of employment as a bus driver was significant association with decreasing risk of lung cancer. This is a negative retrospective study of lung cancer risk and exposure to diesel exhaust with study limitations of power, healthy worker, and survivor effects rendering the result of interest but limited weight in rejecting a hypothesis of a causal connection between lung cancer and diesel exhaust. Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references): Reviewer’s Notes:

Susan Buchanan Steenland, K., Deddens, J., and Stayner, L. “Diesel exhaust and lung cancer in the truck- ing industry: exposure-response analyses and risk assessment.” Am J Ind Med. 1998 Sep;34(3):220–8. Background: Diesel exhaust is considered a probable human carcinogen by the Interna- tional Agency for Research on Cancer (IARC). The epidemiologic evidence rests on stud- ies of lung cancer among truck drivers, bus drivers, shipyard workers, and railroad work- ers. The general public is exposed to diesel exhaust in ambient air. Two regulatory agencies are now considering regulating levels of diesel exhaust: the California EPA (ambient lev- els) and the Mine Safety Health Administration (MSHA) (occupational levels). To date, there have been few quantitative exposure-response analyses of diesel and lung cancer based on human data. Methods: We conducted exposure-response analyses among work- ers in the trucking industry, adjusted for smoking. Diesel exhaust exposure was estimated based on a 1990 industrial hygiene survey. Past exposures were estimated assuming that they were a function of (1) the number of heavy duty trucks on the road, (2) the particulate emissions (g/mi) of diesel engines over time, and 3) leaks from trucks’ exhaust systems for long-haul drivers. Results: Regardless of assumptions about past exposure, all analyses resulted in significant positive trends in lung cancer risk with increasing cumulative expo- sure. A male truck driver exposed to 5 micrograms/m3 of elemental carbon (a typical expo- sure in 1990, approximately 5 times urban background levels) would have a lifetime excess risk of lung cancer of 1 to 2% above a background risk of 5%. Conclusions: We found a lifetime excess risk 10 times higher than the 1 per 1,000 excess risk allowed by OSHA in setting regulations. There are about 2.8 million truck drivers in the U.S. Our results depend on estimates about unknown past exposures, and should be viewed as exploratory. They conform reasonably well to recent estimates for diesel-exposed railroad workers done by the California EPA, although those results themselves have been disputed. Data used for this analysis were from a case-control study of decedents in the Teamsters Union. Smoking histories were obtained from next-of-kin. Job-specific elemental carbon measurements in the trucking industry were made (a surrogate for diesel exhaust). Esti- mates of past level of exposure were made based on changes in diesel engine emissions over time and on the increased use of diesel engines over time. Data on vehicle miles traveled by heavy duty trucks was obtained from the FHWA to estimate past exposure. To conduct an exposure-response analysis for diesel exposure and lung cancer. 1,237 long-haul drivers, 297 short-haul drivers, 164 dockworkers, 88 mechanics, and 120 workers outside the trucking industry. Short- and long-haul drivers, mechanics, dockworkers, and controls outside the trucking industry without occupational diesel exposure. The exposures assigned to individual workers were crude estimates not based on measure- ments of actual exposure. Intrinsic in any risk assessment is the estimation error when eval- uating exposures. Working Conditions (Environmental except sleeper berth) Results from a previous study using this database were reported here and showed that both short-haul and long-haul drivers had 3 to 4 times the residential background exposure to elemental carbon and that risk for lung cancer increased with cumulative exposure (Table I). Logistic regression for lung cancer and cumulative exposure showed that models with 30 Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references):

31 cumulative exposure in quartiles were significant at the highest level of exposure. “In sum- mary, our data suggest a positive and significant increase in lung cancer risk with increas- ing estimated cumulative exposure to diesel exhaust among workers in the trucking indus- try.” (p. 228) This study used a large cohort as well as state-of-the-art exposure assessment methods to show both increased risk for lung cancer with exposure to diesel exhaust and a dose- response trend. Reviewer’s Notes:

Susan Buchanan Tuntiseranee, P., Olsen, J., Geater, A., and Kor-anantakul, O. “Are long working hours and shiftwork risk factors for subfecundity? A study among couples from southern Thailand.” Occup Environ Med. 1998 Feb;55(2):99–105. Objective: To estimate the effect of long working hours and shift work on time to preg- nancy. Methods: Cross-sectional samples with retrospective data collection from two 700 bed hospitals at secondary to tertiary care level in Hatyai district, Songkhla Province, Thai- land. The study was conducted from March 1995 to November 1995 among 1,496 pregnant women attending the antenatal clinics. Subfecundity was defined as time to pregnancy longer than 7.8, 9.5, or 12 months (time to pregnancy was calculated from the date at which the couples started having sexual relations without any contraception until last menstrual date). Results: The descriptive analyses were restricted to 1,201 planned pregnancies and the analytical part to 907 working women. Separate analyses on primigravid women were also done. Logistic regressions adjusted for age, education, body mass index, menstrual reg- ularity, obstetric and medical history, coital frequency, and potential exposure to repro- ductive toxic agents, showed an odds ratio (OR) associated with female exposure to long working hours of 2.3 (95% CI 1.0–5.1) in primigravid and 1.6 (1.0–2.7) in all pregnant women. Male exposure to long working hours and shift work showed no association with subfecundity. The OR of subfecundity was highest when both partners worked >70 hr per week irrespective of the cut off point used OR 4.1 (95% CI 1.3–13.4) in primigravid women; OR 2.0 (95% CI 1.1–3.8) in all pregnant women). Conclusions: Long working hours is a risk factor for subfecundity especially for women. Shift work was not associated with subfecundity in this study. Data is from a consecutive sample of 1,496 pregnant women who received antenatal care at two large public hospitals. Using Thai women to study this issue was deemed favorable because some potential confounders had little variation in this population (most Thai women do not smoke, drink little alcohol or coffee, and many work under physically demanding con- ditions). A fecundity questionnaire was used which included information on the time the woman began to have regular intercourse without any contraception and other exposure fac- tors of both partners. Working hours per week were stratified to 3 levels: <60, 61 to 79, >71. This study aimed at examining the problem of impaired fecundity (the ability to produce a pregnancy that survives to recognition) as a result of long working hours and shift work in southern Thailand. 1496 Thai women n/a Due to sample population of pregnant women, infertile women were excluded so might have resulted in less significant results. No information on occupation. Time on Task Results of the model that included women’s working hours only (not couples’ working hours) showed that working >71 hr per week (compared with <60 and 61 to 70 hr per week) was a significant risk factor for time to pregnancy of >9.5 months. For the model including couples’ working hours, time to pregnancy was significantly increased when both couples worked >71 hr per week. Both of these models controlled for coital frequency. 32 Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references):

33 “Woman and men working >71 hr per week had the highest percentage of subfecundity both among first pregnancies and the total sample, and shift work had a similar distribution of subfecundity in both groups for both men and women.” (p. 7 of 12) “Our findings imply that long working hours could have an adverse effect on the fecundity of the couple which goes beyond the effect on libido and sexual activity.” (p. 10 of 12) This study suggests that working more than 71 hr per week is associated with a prolonged time to achieving pregnancy. Tests for dose response were not performed. Reviewer’s Notes:

Susan Buchanan van der Hulst, M.. “Long workhours and health.” Scand J Work Environ Health. 2003 Jun;29(3):171-88. Comment in: Scand J Work Environ Health. 2003 Jun;29(3):167–9. This paper summarizes the associations between long work hours and health, with special attention for the physiological recovery and behavioral life-style mechanisms that may explain the relationship. The evidence for these mechanisms has not been systematically reviewed earlier. A total of 27 recent empirical studies met the selection criteria. They showed that long work hours are associated with adverse health as measured by several indicators (cardiovascular disease, diabetes, disability retirement, subjectively reported physical health, subjective fatigue). Furthermore, some evidence exists for an association between long work hours and physiological changes (cardiovascular and immunologic parameters) and changes in health-related behavior (reduced sleep hours). Support for the physiological recovery mechanism seems stronger than support for the behavioral life-style mechanism. However, the evidence is inconclusive because many studies did not control for potential confounders. Because of the gaps in the current evidence and the method- ological shortcomings of the studies in the review, further research is needed. The review was limited to articles published in peer-reviewed psychological and medical journals in the English language published between January 1996 and June 2001. Criteria for review were studies which included working populations with at least some participants working 40 hr per week, work hours reported per day or per week, health status as outcome measures, statistical tests for association between extended hours and the outcome measures. To provide an up-to-date overview of recent empirical research on extended work hours and health and also an overview of the main conclusions of these studies. The final selection included 27 articles reporting results from 28 studies in 26 independent samples. Various working populations The term “long work hours” had various meanings depending on the study. Driver Health (General) “Long work hours were associated with an increased risk of cardiovascular disease but a decreased risk of hypertension.” “Working long hours was associated with increased risk of disability retirement and decreased sickness absence.” “Long work hours appeared to be associated with impaired physical health and fatigue.” “Regarding psychological health, long work hours were associated with social dysfunction and confusion, but associations with depression-related outcomes were mixed.” “These results show that there is a good reason to be concerned about the possible detrimental effects of long work hours on health, in particular cardiovascular disease, diabetes, illnesses leading to disability retirement, sub- jectively reported physical ill health, and subjective fatigue.” “It can be concluded that there is evidence of a link between long work hours and ill health, but there is a serious shortage of well-controlled studies that can confirm and strengthen the evidence.” (p. 183) This study is a review of the literature covering a very large topic. “These results show that there is a good reason to be concerned about the possible detrimental effects of long work hours on health, in particular cardiovascular disease, diabetes, illnesses leading to disabil- ity retirement, subjectively reported physical ill health, and subjective fatigue.” 34 Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references): Reviewer’s Notes:

35 Susan Buchanan Boshuizen, H.C., Bongers, P.M., and Hulshof, C.T. “Self-reported back pain in tractor driv- ers exposed to whole-body vibration.” Int Arch Occup Environ Health. 1990;62(2):109–15. A postal questionnaire on symptoms of ill health and exposure to WBV was completed by 577 workers (response rate 79%) who were employed in certain functions by two compa- nies 11 years before. The relationship between the occupational history of driving vibrat- ing vehicles (mainly agricultural tractors) and back pain has been analyzed. The prevalence of reported back pain is approximately 10% higher in the tractor drivers than in workers not exposed to vibration. The increase is mainly due to more pain in the lower back and more pain lasting at least several days. A vibration dose was calculated by assigning each vehi- cle a vibration magnitude, estimated on the base of vibration measurements. The prevalence of back pain increases with the vibration dose. The highest prevalence odds ratios are found for the more severe types of back pain. These prevalence odds ratios do not increase with the vibration dose. This might be due to health-related selection which is more pronounced for severe back pain than for back pain in general. The two components of the vibration dose, duration of exposure and estimated mean vibration magnitude, have also been con- sidered separately. Back pain increases with duration of exposure but it does not increase with the estimated mean magnitude of vibration. This is probably due to the inaccuracy of this estimate. The higher prevalence of back pain in tractor drivers might be (partly) caused by WBV, but prolonged sitting and posture might also be an influence. The study population consisted of workers employed by two state companies; 577 workers responded to a mailed questionnaire containing items on exposure to WBV, symptoms of musculoskeletal disease, and potential confounders. Vibration exposure was estimated using measurements taken at the two companies. This study investigates the prevalence of back pain in drivers of agricultural vehicles in rela- tion to past exposure to WBV. 577 drivers Tractor drivers No information on how study population was selected. Prevalence of back pain was self-reported. Working Conditions (Environmental except sleeper berth) Three types of vibration exposure variables were used. For vibration dose expressed as total years of exposure multiplied by measured vibration magnitude, LBP, frequent or long last- ing LBP were both significant at all levels of exposure and increased with increasing expo- sure. A significant dose-response trend was seen for the three most common types of back pain. (Table 3, p. 112 and text p. 111) For vibration dose expressed as vibration magnitude correcting for duration of exposure and other confounders, frequent or long-lasting LBP were significantly associated with higher doses of vibration. (Table 4, p. 112) Vibration exposure measured in years of full-time exposure showed generally higher but insignificant odds ratios for back pain with increased exposure. (Table 5, p.113) There is a dose-response trend of more frequent back symptoms with increasing duration of exposure to vibration. This should not be affected by actual level of vibration determined by truck or seat type, or road conditions. The published abstract of this study does not ade- quately reflect the data contained in the tables. Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references): Reviewer’s Notes:

Susan Buchanan Caruso, C.C., Lusk, S.L., and Gillespie, B.W. “Relationship of work schedules to gas- trointestinal diagnoses, symptoms, and medication use in auto factory workers.” Am J Ind Med. 2004 Dec;46(6):586–98. Background: GI complaints are common in shift workers. This study examines the rela- tionship between work schedules and GI symptoms, medications, and diagnoses. Methods: In a cross-sectional survey of 343 U.S. auto factory workers, four work schedule variables were examined: assigned shift, number of hours worked, number of night hours, and sched- ule variability. Multiple regression tested the relationship between GI outcomes and work schedule variables while controlling for covariates. Results: The evening shift was associ- ated with more GI symptoms and GI diagnoses. Unexpectedly, more consistent work times were associated with having a GI diagnosis. As schedule variability increased the proba- bility of GI medication use increased in low noise exposure. Conclusion: Findings suggest that evening shift and widely varying work start and end times may increase risks for GI disturbances. A convenience sample of auto workers in the Midwest United States. Participants com- pleted a 20-page questionnaire which was designed for a larger cross-sectional study. This study used data on GI risk factors, specifically demographics, smoking, noise exposure, ASA and NSAID use, and stress. Work hours were documented using clock-in and clock- out records for 1 month. To examine the relationship between work schedules (shift work and overtime) and self- reported GI symptoms, GI medication use, and GI diagnoses. 343 workers in one auto factory Auto factory workers who were skilled or unskilled hourly wage earners No information on how participants were recruited. Did only those with health problems volunteer? Healthy worker effect: inclusion criteria excluded those who had worked at the plant for less than 5 years. Symptoms were self-reported. The significant GI outcome in this study was GI medication use, not diagnoses or symptoms. Is this an adequate marker for GI disease? Time on Task a. GI symptoms: significant increase in symptoms for evening shift and insignificant increase after 30 hr/month of night work. b. GI diagnosis: significant increase in GI diag- nosis with schedule variability and evening shift. c. GI medication use: significant increase in GI med use with clock-out variability and combined clock-in and-out variability over a 7-day period. “a 4-hr increase in clock-out variability over the 7-day period increased the odds for GI medication use by 30.” (p. 592) “Over the 28-day period, 40 extra hours of work (or an additional 10 hr per week) increased the odds for GI medication use by 23%.” (p. 593) “Total number of hours worked showed only a modest positive relationship with GI med- ication use, and no relationship with GI symptoms or diagnosis.” (p. 595) 36 Primary Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references):

37 “Findings from the current study suggest that time of work (day vs. evening) and the con- sistency of the schedule may have a greater influence on these GI outcomes than overtime.” (p. 595) Schedule variability, evening shift, and number of hours worked per week are significantly associated with adverse GI outcomes. Reviewer’s Notes:

Susan Buchanan Boffetta, P. and Silverman, D.T. “A meta-analysis of bladder cancer and diesel exhaust exposure.” Epidemiology. 2001 Jan;12(1):125–30. The aim of this study is to review and summarize the available epidemiologic studies of bladder cancer and occupational exposure to diesel exhaust. We retrieved relevant studies and abstracted their characteristics and results. We assessed the heterogeneity of the results to decide whether to perform a fixed-effects model meta-analysis. We identified 35 relevant studies. No overall meta-analysis was performed because of heterogeneity in results. Results of railroad workers (N = 14) suggested an increased occurrence of bladder cancer, but we did not conduct a meta-analysis. The summary relative risk (RR) among truck driv- ers was 1.17 (95% CI = 1.06–1.29, 15 studies) and that among bus drivers was 1.33 (95% CI = 1.22–1.45, 10 studies). Ten studies considered diesel exhaust exposure based on a job exposure matrix or a similar approach; the summary relative risk for these studies was 1.13 (95% CI = 1.00–1.27). A positive dose-response relationship was suggested by 10 of the 12 studies that provided relevant information. The summary relative risk for high diesel exposure was 1.44 (95% CI = 1.18–1.76). There was some evidence of publication bias, however, with a lack of small studies with null or negative results. Our review suggests that exposure to diesel exhaust may increase the occurrence of bladder cancer, but the effects of misclassification, publication bias, and confounding cannot be fully taken into account. Searched epidemiologic literature for studies on cancer after exposure to diesel exhaust and for studies on occupational risk factors for bladder cancer. Concentrated on 5 occupational groups including truck drivers. To summarize available results of epidemiologic studies of the association between occu- pational exposure to diesel exhaust and occurrence of urinary bladder cancer. 29 studies on bladder cancer and exposure to diesel exhaust Truck drivers, no further characterization Working Conditions (Environmental except sleeper berth) Fifteen results were available for truck drivers. Exposure was characterized by either years of employment or job exposure matrix. For exposure to diesel exhaust characterized as “high,” relative risk was 1.44 and significant. For “any exposure,” relative risk was 1.23 and significant. See Table 5. “Out of 12 results for ‘heavy exposure,’ 10 were higher than their corresponding results for ‘any exposure,’ and only one of the remaining was lower.” (p. 129) Meta-analysis showing positive evidence for increased risk of bladder cancer among truck drivers with “any exposure” to diesel exhaust. Truck drivers with “high” exposure were sig- nificantly more likely to have bladder cancer than those with lower levels of exposure. 38 Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references): Reviewer’s Notes:

39 Susan Buchanan Lings, S. and Leboeuf-Yde, C. “Whole-body vibration and low back pain: a systematic, crit- ical review of the epidemiological literature 1992–1999.” Int Arch Occup Environ Health (2000);73: 290–297. Objectives: A previous extensive review of the literature including that from the middle of 1992 concluded that WBVs may contribute to low back pain, but that the exposure-response relationship had not been clarified. We reviewed the literature of the past 7 years to find out: (i) whether there is evidence in the recent epidemiological literature for a causal associa- tion between WBV and LBP, and (ii) if there is evidence in the recent literature for a dose- response relationship between WBV and LBP. Methods: All relevant epidemiological arti- cles, which were obtained through a search in the databases MEDLINE, OSH-ROM, and TOXLINE, and through personal communication, were reviewed independently by the two authors, using a checklist. Results: Twenty-four original articles concerning the association between WBV and the lower back were retained for use. Only seven articles passed our pre- determined quality criteria. Of the seven reports, one showed increased frequency of lum- bar prolapse in occupational drivers, and six showed LBP to be more frequent in WBV- exposed groups. Only two of the four articles reporting on dose showed a dose-response association. Conclusions: Despite the lack of definite evidence, we found sufficient reasons for the reduction of WBV-exposure to the lowest possible level. If new knowledge is to be produced, good prospective studies with repeated measurements of exposure, analyses of work postures, and clear definitions and subgroupings of LBP are needed. Other research in this field should be given up, and the resources used for more important issues, as the size of the problem of WBV is probably on the decrease because of the technical prophy- lactic developments that are already in progress. Literature review of MEDLINE, OSH-ROM, and TOXLINE of all original epidemiologi- cal articles published from 1992-1999. They were reviewed by the two authors, indepen- dently using predetermined quality criteria. To conduct a review of the literature on WBV and LBP since the issue was last reviewed in 1992. Questions addressed were: Is there evidence for a definite association between WBV and LBP? Is there evidence for a dose-response relationship between WBV and LBP? 24 original reports were identified: 21 passed initial screening, 7 studies fulfilled at least 5 of the 6 quality criteria. Various Authors seemed a little opinionated, may have had an agenda Working Conditions (Environmental except sleeper berth) Six reports showed LBP to be more frequent in study groups and one showed increased fre- quency of hospitalization for disc herniation in drivers. Of the four studies on dose-response, two showed an association. “. . . despite at least 24 epidemiological publications address- ing the question, the evidence still remains weak.” (p. 291) Authors’ conclusion: “The six reports that best fulfilled our quality criteria were predomi- nantly in favour of a positive association between WBA and LBP . . . Hence it can still be concluded that here is probably an association between WBV and LBP,” ( but not causal- Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references):

ity) “Existing knowledge yields sufficient reasons for reducing exposure to the lowest pos- sible level.” (p. 296) Although the authors give mixed conclusions about the effect of WBV on LBP, most of the studies included in the literature review found positive associations. However, evidence for dose-response was weak. 40 Reviewer’s Notes:

41 Peter Orris Jensen, Marianne V. Tuchsen, F., and Orhede, E. “Prolapsed Cervical Intervertebral Disc in Male Professional Drivers in Denmark, 1981–1990: A Longitudinal Study of Hospital- izations.” Spine 1996, October 21(20): 2352–2355. Study Design: This study of professional drivers is a part of a longitudinal record linkage study of all economically active men in Denmark, identified on January 1, 1981. Informa- tion about the main occupation was identified in 1980. The cohort was followed for first hospitalization with prolapsed cervical intervertebral disc until December 31, 1990. Objec- tives: To examine the risk of prolapsed cervical intervertebral disc in all Danish professional drivers, and to analyze exposures of the male drivers in a sample of all Danish male drivers. Methods: A standardized hospitalization ratio was calculated for each subgroup of drivers using all economically active people as the standard. Additional exposure information was extracted from a national survey on work environment. Almost all men in occupations involving professional driving had a statistically significant elevated risk of being hospi- talized with prolapsed cervical intervertebral disc. Conclusions: Professional driving is a risk factor for prolapsed cervical intervertebral disc. Methods: This study of professional drivers is a part of a longitudinal record linkage study of all economically active men in Denmark, identified on January 1, 1981. Information about the main occupation was identified in 1980. The cohort was followed for first hospi- talization with prolapsed cervical intervertebral disc until December 31, 1990. A standard- ized hospitalization ratio was calculated for each subgroup of drivers using all economi- cally active people as the standard. Additional exposure information was extracted from a national survey on work environment. Only a few studies on occupation and prolapsed cervical intervertebral disc have been pub- lished. These studies suggest that professional driving may be a risk factor for development of prolapsed cervical intervertebral disc. Drivers are exposed to WBVs, heavy lifting, and a sedentary position. Other potential exposures are accelerations and decelerations and whiplash accidents. Such exposures may be involved in the causation of prolapsed cervical intervertebral disc. 1.3 million economically active men in Denmark Various Unable to separate WBV from other musculoskeletal stressors on drivers Driver Health (General) Almost all men in occupations involving professional driving had a statistically significant elevated risk of being hospitalized with prolapsed cervical intervertebral disc. An objective prospective study identifying professional driving as a risk factor for the development of prolapse of a cervical intervertebral disc. Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references): Reviewer’s Notes:

Susan Buchanan Gustavsson, P., Plato, N., Hallqvist, J., Hogstedt, C., Lewne, M., Reuterwall, C., and Scheele, P. “A population-based case-referent study of myocardial infarction and occupa- tional exposure to motor exhaust, other combustion products, organic solvents, lead, and dynamite. Stockholm Heart Epidemiology Program (SHEEP) Study Group.” Epidemiol- ogy. 2001 Mar;12(2):222–8. This case-control study investigated the risk of MI from occupational exposure to motor exhaust and other combustion products. We identified first-time, nonfatal MIs among men and women 45 to 70 years of age in Stockholm County from 1992 through 1994. We selected referent subjects from the population to match the demographic characteristics of the cases. A lifetime history of occupations was obtained by questionnaire. The response rate was 81% for the cases and 74% for the referents, with 1,335 cases and 1,658 referents included in the study. An occupational hygienist assessed occupational exposures, coding the intensity and probability of exposure for each subject. We adjusted relative risk esti- mates for tobacco smoking, alcohol drinking, hypertension, diabetes mellitus (DM), being overweight, and physical inactivity at leisure time. The relative risk of MI was 2.11 (95% CI = 1.23–3.60) among those who were highly exposed and 1.42 (95% CI = 1.05–1.92) among those who were intermediately exposed to combustion products from organic mate- rial. We observed an exposure-response pattern, in terms of both maximum exposure inten- sity and cumulative dose. Exposure to dynamite and organic solvents was possibly associ- ated with an increased risk. The other exposures were not consistently associated with MI. Case-control study of first-time MI. Cases were identified from intensive care units in Stockholm County. Controls were selected from a computerized population register and were matched according to sex, age, and hospital catchment area. Subjects completed ques- tionnaires on occupational history. A job exposure matrix was created by industrial hygien- ists using unpublished and published occupational hygiene reports, personal contacts and professional experience to quantify intensity of exposure using estimated exposure preva- lence within each occupation (in terms of annual average of 8-hr work day exposures to motor exhaust.) Relative risks were adjusted for smoking, alcohol intake, hypertension, weight, DM, and physical inactivity. To investigate the risk of MI from occupational exposure to motor exhaust and other com- bustion products. 1,335 case and 1,658 controls Did not specify Those who survived MI were interviewed. Those not surviving were excluded (history of exposure not taken from surviving family members). Exposures to exhaust were estimated, not measured. Did not control for cholesterol results. Did not specify type of exhaust. Working Conditions (Environmental except sleeper berth) (Actual journal page numbers are not given in this on-line document.) Working conditions: There was a non-significant elevation of relative risk of MI with moderate exposure to motor exhaust. No dose response trend was seen. There was a significantly increased rela- tive risk of MI with high or intermediate exposure to combustion products, (besides motor 42 Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references):

43 exhaust). The same results were found when cumulative exposure was estimated. (See Tables 2 and 4.) “We found some indications of an increased risk of MI in association with exposure to motor exhaust, but no firm evidence of an exposure-response relation.” The results are suggestive of increasing MI risk with cumulative exposure to motor exhaust. Reviewer’s Notes:

Susan Buchanan Chen, J.C., Dennerlein, J.T., Shih, T.S., Chen, C.J., Cheng, Y., Chang, W.P., Ryan, L.M., and Christiani, D.C. “Knee pain and driving duration: a secondary analysis of the Taxi Driv- ers’ Health Study.” Am J Public Health. 2004 Apr;94(4):575–81. Objectives: We explored a postulated association between daily driving time and knee pain. Methods: We used data from the Taxi Drivers’ Health Study to estimate 1-year prevalence of knee pain as assessed by the Nordic musculoskeletal questionnaire. Results: Among 1,242 drivers, the prevalence of knee pain, stratified by duration of daily driving (≤6, >6 through 8, >8 through 10, and >10 hr), was 11%, 17%, 19%, and 22%, respectively. Compared with driving 6 or fewer hr per day, the odds ratio of knee pain prevalence for driv- ing more than 6 hr per day was 2.52 (95% CI = 1.36–4.65) after adjustment for socioeco- nomic, work-related, and personal factors in the multiple logistic regression. Conclusions: The dose-related association between driving duration and knee pain raises concerns about work-related knee joint disorders among professional drivers. Taxi drivers in Taipei city were recruited during free government physical exams. Ques- tionnaires were completed which included information on daily driving hours, among other work factors, and presence of knee pain in the previous 12 months. To test the hypothesis that prolonged driving is associated with increased knee pain among taxi drivers. 1,242 taxi drivers (of at least 1 years’ duration) Taxi drivers Used self-reports of knee pain. Presence of pain does not necessarily indicate a medical condition. Shifts/Time of Day/Circadian Workers with >10 hr of daily driving had significantly increased risk of knee pain. There was a dose response in history of knee pain and daily driving times of ≤6 hr, 6 to 8 hr, 8 to 10 hr, and >10 hr (all significant) when controlled for age, gender, BMI, income, other demographics, and physical exertion during work and leisure time, and professional senior- ity. No associations were found between knee pain and vehicle manufacturers or engine sizes. Authors’ conclusion: “Our exploratory analyses of the TDHS (Taxi Drivers’ Health Study) baseline data revealed a strong and robust association between long driving times and knee pain. The public health impact of work-related knee pain among professional driv- ers could be substantial.” Agree with previous quote. 44 Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references): Reviewer’s Notes:

45 Susan Buchanan Barton, J. and Folkard, S. “Advancing Versus Delaying Shift Systems.” Ergonomics 1993;36(1-3):59–64. Two-hundred sixty-one shift workers from a range of UK industrial and service organiza- tions took part in a study to determine the impact of the direction of shift rotation on the health and well-being of the individuals concerned. All the systems were continuous, rotat- ing over three shifts. Systems were classified according to whether they delayed (i.e., rotated in a forward direction) or advanced (i.e., rotated in a backward direction). In addi- tion, advancing systems were divided into those which incorporated a quick return (i.e., a break of only 8 hr when changing from one shift to another) and those which did not. The results add some support for the use of delaying as opposed to advancing systems, and high- light the detrimental affects of incorporating a quick return into an advancing system. All subjects completed the Standard Shift Work Index. ANCOVA was performed to deter- mine the effect of the direction of shift rotation on each outcome measure. To examine the relative effect of advancing or delaying systems on shift workers. A total of 261 industrial and service shift workers from a range of occupations took part in the study Shift workers from steel industry, power industry, post office, police force, and air traffic control officers There was no information given on the sampling method, whether the participants were vol- untary or randomly selected. Shifts/Time of Day/Circadian Compared with the delayed rotating shift system, workers on the advancing system were significantly more likely to complain of digestive and cardiovascular disorders, chronic fatigue, and cognitive anxiety. (See Table 1, p. 61.) “Comparing advancing systems with and without a quick return produced few significant differences, yet overall, it was the former who reported poorer physical health.” (p. 63) “In conclusion it would appear that the critical feature may not be related entirely to the direction of rotation but to a combination of direction and the length of break when chang- ing from one shift to another.” (p. 64) This article adds to the body of literature associating a change in sleep schedule (a.k.a. cir- cadian rhythm) with GI and cardiovascular effects. Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references): Reviewer’s Notes:

Susan Buchanan Morgan, L., Arendt, J., Owens, D., et al. “Effects of the endogenous clock and sleep time on melatonin, insulin, glucose and lipid metabolism.” J Endocrin 1998;157:443–451. This study was undertaken to determine whether the internal clock contributes to the hor- mone and metabolic responses following food, in an experiment designed to dissociate internal clock effects from other factors. Nine female subjects participated. They lived indoors for 31 days with normal time cues, including the natural light and darkness cycles. For 7 days they retired to bed from 0000 to 0800. They then underwent a 26-hr ‘constant routine’ (CR) starting at 0800 h, being seated awake in dim light with hourly 88 Kcal drinks. They then lived on an imposed 27-hr day for a total of 27 days. A second 26-hr CR, start- ing at 22 hr was completed. During each CR salivary melatonin and plasma glucose, triglyc- eride (TAG), non-essential fatty acids (NEFA), insulin, gastric inhibitory peptide (GIP) and glucagons-like peptide-1 (GLP-1) were measured hourly. Melatonin and body temperature data indicated no shift in the endogenous clock during the 27-hr imposed schedule. Post- prandial NEFA, GIP and GLP-1 showed no consistent effects. Glucose, TAG, and insulin increased during the night in the first CR. There was a significant effect of both the endoge- nous clock and sleep for glucose and TAG, but not for insulin. These findings may be rel- evant to the known increased risk of cardiovascular disease amongst shift workers. Subjects were observed for 31 days and were required to live on an imposed 27-hr day cycle. Activity was monitored with wrist monitors and rectal temps were recorded. Blood levels for triacylglycerol, insulin, and glucagon-like peptide. Salivary melatonin was measured. To determine to what extent the internal clock contributes to the hormonal and metabolic responses following a meal. 9 female undergraduates n/a Testing was performed in experimental conditions which might not reflect real life scenarios. Shifts/Time of Day/Circadian “Dissociation of the internal clock and sleep in the second constant routine leads to a dampening of the peak response to glucose and the appearance of two comparable peaks, suggesting a ‘spreading’ of glucose intolerance such that it occurs at two periods of the day.” (p. 448–449) “The present study has shown for the first time that the length of wake- fulness also has an effect on glucose tolerance, independent of any circadian rhythm or sleep itself.” (p. 449) This group previously reported that immediately after a simulated 9-hr advance, such as might be found in rotating shift work, postprandial insulin and glucose responses to a stan- dard mixed meal were significantly greater than to the same meal at the same external clock time before the phase shift. The changes were suggestive of insulin resistance, a risk factor for cardiovascular disease. This study takes this issue a step further and tries to separate out the possible effect of a cir- cadian rhythm change. Results showed that insulin resistance indeed worsened with a longer sleep-wake cycle but was independent of changes in the internal clock or circadian rhythm. 46 Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references): Reviewer’s Notes:

47 Susan Buchanan Scott, A. “Shift Work and Health.” Primary Care Dec 2000;27(4):1057–1078. Night work and rotating shift work disrupt the circadian timing system. This disruption may produce significant deleterious symptoms in some workers. Certain medical conditions may be aggravated by shift-work scheduling, and shift workers are at increased risk of experi- encing cardiovascular, GI, and reproductive dysfunction. Vulnerable individuals may develop clinical depression when working shifts. Primary care practitioners may intervene by providing medical surveillance and education programs for shift-working patients and their families. Written as a chapter with 166 references. It is not original research but is an excellent review of the current literature up to 2000. This is a chapter on Occupational and Environmental Medicine in a hard bound journal. It offers an overview of circadian rhythms and the health effects of night work and sleep depri- vation, and offers a review of specific medical disorders associated with shift work. n/a n/a This is not original research. It assumes validity of its references. Shifts/Time of Day/Circadian: Circadian rhythm: “. . . each time the work schedule rotates, for a period of time after the time shift, the circadian system will be in a desynchronized state.” (p. 1059) Shift-work intolerance: “Up to 20% of shift workers may have a disproportionate number of symptoms of illness when assigned to chronobiologically poorly designed shift-work schedules involving night work.” (p. 1061) “Specific factors that affect shift work tolerance include: . . . rotating or fixed, number of nights worked consecutively, frequency of week- ends off, length of shift and starting time, overtime requirements, predictability of sched- ule.” (p. 1061) GI Disorders: “Gastrointestinal dysfunction is common in shift workers. . . . Some studies have not found an increased incidence of peptic ulcer disease in shift workers, but the majority of studies addressing this outcome have. Including non-English reports, 16 of 24 studies evaluating PUD and shift work found shift workers to be at greater risk of devel- oping PUD than day workers. . . . Circadian rhythm disruption also contributes to shift- work related GI dysfunction.” (p. 1062) Cardiovascular morbidity: “Although there are studies that have not found changes in lipid profiles related to shift work, a recent thorough review of this research concluded that the better studies do indicate that shift workers have somewhat higher levels of cholesterol as well as triglycerides.” “Although early studies concluded shift work was not associated with an increase in CVD, most of the more recent, better epidemiologically designed studies have found an increased risk of CVD.” (p. 1063) Reproductive Health: Studies quoted showed shift work and rotating shift work to be asso- ciated with higher prematurity rate, low birth weight, spontaneous abortion, and decreased fertility rate.” (p. 1064-65) Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references):

Exacerbation of Medical Disorders: “Shift work also may aggravate certain medical disorders related to circadian rhythm disruption, psychosocial stress, or sleep deprivation. Conditions that may be exacerbated or aggravated by irregular schedules or night work and are therefore potential contraindications for shift work include: GI disorders, DM, epilepsy, cardiovascu- lar disease, psychiatric disorders, sleep disorders, reproductive dysfunction.” (p. 1066) This chapter, with 166 references, confirms the multiple health issues related to shift work and rotating shift work including GI, cardiovascular, and reproductive health. 48 Reviewer’s Notes:

49 SUMMARY OF FINDINGS OF LITERATURE The review of the available literature has excluded the end points of fatigue, accidents, and road safety. The available information has reviewed topics concerning driver health, with emphasis on chronic conditions. The literature indicates lung cancer is likely caused by exposures to diesel exhaust and the longer that exposure lasts the more likely it is that a cancer will develop. Though the evidence for exposure as a truck driver causing bladder can- cer is less robust than that for cancer of the lung, it remains likely that there is such a relationship and that it is governed by a positive dose-response curve. The literature offers evidence that cardiovascular disease is caused in part by truck driving and its risk increases with the duration of this activity and the disruption of the sleep cycle. The literature indicates that it is clear based on exposure assessments and the knowledge of the relationship between noise and hearing loss that this could well be a result of a working lifetime as a driver with increasing likelihood based on duration of exposure depending on truck design. This effect would be mitigated by improvement in cab design reported to be occurring with a consequent reduction in the intensity of noise that reaches the driver. The evidence concerning a relationship between WBV and musculoskeletal effects, such as LBP syndrome, relies pri- marily on self-reporting and application of risks derived from other environments. There are several studies available that contain objective evidence of vertebral pathology related to an occupation as a professional driver. The available litera- ture supports the hypothesis that there is likely a causative relationship between professional driving and a variety of vertebral disorders as well as LBP syndrome. While it is log- ical to assume, and the literature suggests, a role for WBV in the genesis of these disorders, it cannot be established based on current published materials. The literature related to CMV driving and other muscu- loskeletal disorders suffers from the same limitations and while a causative relationship is logical it can only be viewed as suggestive within this context. The literature indicates that GI disorders would be expected to be impacted by varying shift assignments and disruption to normal circadian rhythm. While the information currently available documents an increase in symptoms, it is inade- quate to implicate the specific risk factors that impact on these symptoms. The literature suggests, but does not establish, that disrup- tion of circadian rhythm may have negative impacts on the general health status of workers. The stabilization of shift especially when stabilized to a day schedule appears to have a beneficial effect on subjective health complaints though sta- bilizing to an evening or night schedule may not provide the same benefit. Finally, the literature does not contain definitive information concerning the relationship between reproductive health and duration of driving, nor on the effects of prolonged work hours or increased driving time from 10 to 11 hr while decreasing overall work time from 15 to 14 hr on the general health of workers. No data are available concerning the effects of allowing for increased sleep time from 6 to 8 hr in an adult working population. 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Bunn, W.B. “What is New in Diesel.” Int Arch Occup Envi- ron Health. 2002 Oct;75 Suppl:S122–32. Burdorf, A. and Swuste, P. “The effect of seat suspension on exposure to whole-body vibration of professional drivers.” Ann Occup Hyg. 1993 Feb;37(1):45–55. Chen, J.C., Chang, W.R., Shih, T.S., Chen, C.J., Chang, W.P., Dennerlein, J.T., Ryan, L.M., and Christiani, D.C. “Using exposure prediction rules for exposure assessment: an example on whole-body vibration in taxi drivers.” Epi- demiology. 2004 May;15(3):293–299. Claude, J.C., Frentzel-Beyme, R.R., and Kunze, E. “Occu- pation and risk of cancer of the lower urinary tract among men. A case-control study.” Int J Cancer. 1988 Mar 15;41(3):371–379. Cruz, C., Della Rocco, P., and Hackworth, C. “Effects of quick rotating shift schedules on the health and adjustment of air traffic controllers.” Aviat Space Environ Med. 2000 Apr;71(4):400–7. Figa-Talamanca, I., Cini, C., Varricchio, G.C., Dondero, F., Gandini, L., Lenzi, A., Lombard, F., Angelucci, L., Di Grezia, R., and Patacchioli, F.R. “Effects of prolonged autovehicle driving on male reproduction function: a study among taxi drivers.” Am J Ind Med. 1996 Dec;30(6):750–8. Funakoshi, M., Taoda, K., Tsujimura, H., and Nishiyama, K. “Measurement of whole-body vibration in taxi drivers.” J Occup Health. 2004 Mar;46(2):119–24. Garshick, E., Laden, F., Hart, J., Rosner, B., Smith, T., Dockery, D., and Speizer, F. “Lung Cancer in Railroad Workers Exposed to Diesel Exhaust.” Env Health Persp. 2004 Nov.;(112):1539–1543. Harrington, J.M. “Shift work and health—a critical review of the literature on working hours.” Ann Acad Med Singa- pore. 1994 Sep;23(5):699–705. Jensen, O.M., Wahrendorf, J., Knudsen, J.B., and Sorensen, B.L. “The Copenhagen case-referent study on bladder 51 cancer. Risks among drivers, painters and certain other occupations.” Scand J Work Environ Health. 1987 Apr;13(2):129–34. Lyons, J. “Factors contributing to low back pain among pro- fessional drivers: a review of current literature and possi- ble ergonomic controls.” Work. 2002;19(1):95–102 Nakanishi, N., Nishina, K., Yoshida, H., Matsuo, Y., Nagano, K., Nakamura, K., Suzuki, K., and Tatara, K. “Hours of work and the risk of developing impaired fasting glucose or type 2 diabetes mellitus in Japanese male office work- ers.” Occup Environ Med. 2001 Sep;58(9):569–74. Rafnsson, V. and Gunnarsdottir, H. “Mortality among pro- fessional drivers.” Scand J Work Environ Health. 1991 Oct;17(5):312–7. Shields M. “Long working hours and health.” Health Rep. 1999 Autumn;11(2):33-48(Eng); 37–55. Silverman, D.T., Hoover, R.N., Mason, T.J., Swanson, G.M. “Motor exhaust-related occupations and bladder cancer.” Cancer Res. 1986 Apr;46(4 Pt 2):2113–6. Soll-Johanning, H., Bach, E., Olsen, J.H., and Tuchsen, F. “Cancer incidence in urban bus drivers and tramway employees: a retrospective cohort study.” Occup Environ Med. 1998 Sep;55(9):594–8. Spiegel, K. et al. “Impact of Sleep Debt on Metabolic and Endocrine Function.” Lancet. 1999 Oct;354(9188): 1435–1439. Steenland, N.K., Silverman, D.T., and Hornung, R.W. “Case- control study of lung cancer and truck driving in the Team- sters Union.” Am J Public Health. 1990 Jun;80(6):670–4. Steenland, K. and Fine, L. “Shift work, shift change, and risk of death from heart disease at work. “Am J Ind Med. 1996 Mar;29(3):278–81. Stoynev, A.G. and Minkova, N.K. “Circadian Rhythms of Arterial Pressure, Heart Rate and Oral Temperature in Truck Drivers.” Occ Med. 1997 April;47(3):151–154.

LITERATURE REVIEW—FATIGUE According to the Scope of Work, the literature to be reviewed in Task 2 pertains to “hours of service (HOS) and commercial vehicle operator performance and fatigue, espe- cially as they pertain to driver health. The purpose of this facet of the literature review is to provide information that clearly discusses in a scientific, experimental, qualitative, and quanti- tative way the relationship between the hours a person works, drives, and the structure of the work schedule (on-duty/off- duty cycles, time on task, especially time in continuous driv- ing, sleep time, etc.) and the impact of CMV driver fatigue and performance.” PROCESS AND METHODOLOGY The TRANSPORT database from the University of Toronto library system was used for the literature search. The key resource within the database is Transportation Research Information Services (TRIS) from TRB. TRANSPORT is a bibliographic database of transportation research and eco- nomic information. It is produced by the 25-nation Organi- sation for Economic Co-operation and Development (OECD), headquartered in Paris, together with the United States’ TRB and the 31 nations of the European Conference of Ministers of Transport (ECMT). TRANSPORT combines the follow- ing databases: TRIS from TRB includes 300,000 bibliographic citations, most with abstracts, of research information on all surface transportation modes, air transport, and highway safety. International Road Research Documentation (IRRD) from OECD contains 200,000 abstracts on highway research provided by OECD member countries. TRANSDOC from ECMT contains 37,000 abstracts of transportation econom- ics literature as well as bibliographic records provided by the International Union of Railways (UIC). A search for articles after 1995 was performed on the data- base using the following terms: • CMV operators and fatigue • CMV operators, fatigue, and the following – driving performance – driving hours, time on task, duration of work-weeks – length of sleep time, sleep deprivation – shift work, schedule regularity, schedule irregularity – sleep deprivation countermeasure (including naps) – HOS regulations – schedules, shift rotation, multi-day shifts – operational and performance models – alertness, fatigue – distraction and reaction time • Drivers and fatigue • Drivers, fatigue, and the following – Driving performance – Driving hours – Length of sleep time, sleep deprivation – Shift work – Sleep deprivation countermeasure (including naps) – Alertness, fatigue – Distraction and reaction time • CMV operators and – HOS – Hours of work – Work rest schedules – Workload – Sleep schedules – Rest periods – Performance (as opposed to ‘”driving performance”) SELECTION CRITERIA The following are a list of references from the scientific and technical literature concerning HOS and CMV operator per- formance and fatigue, especially as they pertain to driver health. The references focus on experimental studies or sur- veys. Literature reviews and papers focusing on policy have been excluded from this list. Papers focused specifically on crashes as well as sleep deprivation countermeasures, harmful/ toxic substances, technological approaches to CMV driver alertness management, and distraction and reaction time have also been excluded from this list. Primary Sources Primary references met the following selection criteria. Each reference had to address truck driver performance (on road or in driving simulators) and include some measure of performance (vehicle control or critical incidents) in associ- ation with driving. Studies had to involve drivers on typical work-rest schedules, that is, they involved extended hours of driving, driving in a sleep-deprived state, and/or driving at night. The 26 primary references, in order of first author, are listed on page 93. Where available there are abstracts shown 52

53 for each study. In many cases, several publications pertained to the same study. In total, there were 13 distinct studies. These are shown in the following subsection and are reviewed in the Article Summaries, using the format prescribed by FMCSA. Distinct Studies 1. Effects of long hours on critical incidents; Survey of truck drivers and companies in an unregulated state (Australia) Arnold, P.K., Hartley, L.R., Hochstadt, D., and Penna, F. “Hours of work, and perceptions of fatigue among truck drivers.” (1997). Accident Analysis & Prevention, 29 (4) 471–77. 2. Exceeding HOS (New Zealand) and performance; Survey of truck drivers on current level of fatigue, driving and sleep in previous 48 hr; Measures of vehicle control and reaction time in simulator Baas, P.H., Charlton, S., and Bastin, G. (2000). “Sur- vey of New Zealand truck driver fatigue and fitness for duty.” 4th International Conference on Fatigue and Transportation, Fremantle, Western Australia. Charlton, S.G. and Baas, P.H. “Fatigue and fitness for duty of New Zealand truck drivers.” (1998). Road Safety Research, Policing, Education Conference. Wellington, New Zealand. Vol. 2. 214–9. 3. Effects of sleep schedules on performance; Sleep and Lab study; Actigraphic assessment of sleep and sleep log data for long- and short-haul drivers over an extended period—during on and off duty periods; Performance on psychomotor tasks (e.g., Driving simulator, PVT, Walter Reed Performance Assessment Battery) Balkin, T., Thome, D., Sing, H., Thomas, M., Red- mond, D., Wesensten, N., Williams, J., Hall, S., and Belenky, G. (2000). “Effects of sleep schedules on commercial motor vehicle driver performance.” Department of Transportation, Federal Motor Car- rier Safety Administration. FMCSA Tech Brief, 2000/09 (FMCSA-MCRT-00- 015). “Effects of sleep schedules on commercial motor vehicle driver performance—Part 2.” 4. Effects of sleeper berth usage on driver fatigue; Driver performance information: steering, lane departure, braking; Subjective alertness ratings Dingus, T., Neale, V., Garness, S., Hanowski, R., Keisler, A., Lee, S., Perez, M., Robinson, G., Belz, S., Casali, J., Pace-Schott, E., Stickgold, R., Hobson, J.A., The Impact of Sleeper Berth Usage on Driver Fatigue. FMCSA, FMCSA-RT-02-050, Washing- ton, DC, November 2001. Federal Motor Carrier Safety Administration. ”Impact of sleeper berth usage on driver fatigue.” (2002). Report Number: FMCSA-RT-02-050. 5. Team vs. single long-haul driving; Performance and subjective levels of fatigue over 4,500 Km trip (Australia) Feyer, A.M., Williamson, A., and Friswell, R. “Bal- ancing work and rest to combat driver fatigue: An investigation of two-up driving in Australia.” (1997). Accident Analysis & Prevention, 29 (4) 541–53. 6. Time of day effects on performance (e.g., lane posi- tion, speed, etc.) in simulated driving task; effect of naps on performance Gillberg, M., Kecklund, G., and Akerstedt, T. (1996). “Sleepiness and performance of professional drivers in a truck simulator—comparisons between day and night driving.” Journal of Sleep Research, 5, 12–15. 7. Driver sleepiness-related problems; Driver’s health status; Survey of professional drivers on frequency of prolonged driving and near-miss situations Hakkanen, H. and Summala, H. (2000). “Driver sleepiness-related problems, health status, and pro- longed driving among professional heavy-vehicle drivers.” Transportation Human Factors, 2(2), 151–171. 8. Impact of local short-haul operations on driver fatigue; Measures to assess fatigue, inattention and drowsiness; Analysis of critical incidents Hanowski, R. J., Wierwille, W. W., Gellatly, A. W., Early, N., and Dingus, T. A. (2000). “Impact of local short-haul operations on driver fatigue.” Department of Transportation Federal Motor Car- rier Safety Administration. FMCSA Tech Brief, 2001 (FMCSA-MCRT-01-006). “Impact of local/short-haul operations on driver fatigue: Field study.” 9. Comparison of fatigue (objective and subjective measures) and driving performance for single ver- sus team drivers on-the-road Klauer, S.G., Dingus, T.A., Neale, V.L. and Carroll, R.J. (2003). “The effects of fatigue on driver per- formance for single and team long-haul truck driv- ers.” Driving Assessment 2003—The Second International Driving Symposium on Human Fac- tors in Driver Assessment, Training and Vehicle Design. Park City, Utah. 10. Antecedents of fatigue, close calls and crashes among CMV drivers; Survey of CMV drivers Morrow, P.C. and Crum, M.R. (2004). “Antecedents of fatigue, close calls, and crashes among com- mercial motor-vehicle drivers.” Journal of Safety Research, 35 (1). 11. Effects of schedule, loading and recovery on alert- ness and performance (e.g., lane position, speed maintenance, PVT) of CMV drivers driving on a simulator O’Neill, T.R., Krueger, G.P., Van Hemel, S.B., and McGowan, A.L. (1999). “Effects of operating prac- tices on commercial driver alertness.” Rep. No.

54 13. Effects of work-rest schedule on performance, crit- ical incidents. Naps and recovery (U.S.-Canada Study) Wylie, C.D. “Driver drowsiness, length of prior prin- cipal sleep periods, and naps.” (1998). Transporta- tion Development Centre. Report No. TP 13237E. Wylie, C.D., Shultz, T., Miller, J.C., and Mitler, M.M. (1997). “Commercial motor vehicle driver rest peri- ods and recovery of performance.” Wylie, C.D., Shultz, T., Miller, J.C., Mitler, M.M., and Mackie, R.R. (1996). Commercial motor vehi- cle driver fatigue and alertness study.” (Executive Summary & Technical Summary). Mitler, M.M., Miller, J.C., Lipsitz, J.J., Walsh, J.K., and Wylie, C.D. (1997). “The sleep of long-haul truck drivers.” New England Journal of Medicine, 337(11). Freund, D. and Vespa, S. (1997) “U.S./Canada study of commercial motor vehicle driver fatigue and alertness.” Proceedings of the XIIIth World Meet- ing of the International Road Federation, Toronto, Ontario. June 16–20, 1997. Secondary Sources The selection criteria for the secondary references were that they were relevant to issues of fatigue and truck driv- ing but not necessarily involving actual driving by truck drivers or typical truck driver schedules. These are listed on page 99. FHWA-MC-99-140, Office of Motor Carrier and Highway Safety, Federal Highway Administration, Washington, D.C. O’Neill, T.R., Krueger, G.P., Van Hemel, S.B., McGowan, A.L., and Rogers, W.C. (1999). “Effects of cargo loading and unloading on truck driver alertness.” Transportation Research Record, 1686, pp. 42–48. O’Neill, T. R., Krueger, G. P., Van Hemel, S. B., and McGowan, A. L. (1999). “Effects of operating prac- tices on commercial driver alertness.” Rep. No. FHWA-MC-99-140, Office of Motor Carrier and Highway Safety, Federal Highway Administration, Washington, D.C. Rogers, W. (2000). “Effects of operating practices on commercial driver alertness.” Proceeding of the Conference Traffic Safety on Two Continents held in Malmo, Sweden, September 20–22, 1999. Tech Brief (1999) (FHWA-MCRT-99-008) “Effects of operating practices on commercial driver alertness.” 12. Effect of sleep deprivation on performance; Effect of four work-rest schedules (2 complying with HOS regulations; two alternative schedules) in simulator and on-road (Australia) Williamson, A., Feyer, A.M., Friswell, R., and Finlay- Brown, S. (2000). “Demonstration project for fatigue management programs in the road transport indus- try: Summary of findings.” Williamson, A., Feyer, A., and Friswell, R. (1996). “The impact of work practices on fatigue in long distance truck drivers.” Accident Analysis & Pre- vention, Vol. 28, No. 6, 709–719.

55 Dianne Davis, Alison Smiley Arnold, P.K., Hartley, L.R., Hochstadt, D., and Penna, F. “Hours of work, and perceptions of fatigue among truck drivers.” (1997). Accident Analysis & Prevention, 29 (4) 471–77. This paper summarizes the results of a survey conducted with 1,249 truck drivers and 84 management representatives of transport companies. Data were collected in an Australian state which, at the time of the survey, did not restrict driving hours for heavy haulage driv- ers. Regulations were being discussed to limit driving to 14 hr in any 24-hr period and restricting driving hours over the week to 72 hr. The aim of the study was to obtain infor- mation about hours of work and sleep from drivers operating in a state without restrictions on driving hours (i.e., unregulated drivers). Drivers were asked to provide details about their driving and non-driving work schedules and the amount of sleep they had obtained in the past week. They were also asked to give an hour-by-hour record of activities, feelings of fatigue, and encounters with dangerous events over the 24 hr prior to the interview. Drivers and company representatives were interviewed about their perceptions about fatigue (e.g., factors perceived to be related to fatigue, causes, management) and whether they felt fatigue was problematic for truck drivers. A definition of fatigue was not provided. The authors concluded the paper by comparing their data on unregulated drivers’ perceptions about fatigue to those reported by Williamson et al. (1992) for mainly regulated drivers. Survey conducted with 1,249 truck drivers and 84 management representatives of transport companies. Survey conducted at road houses in Australia with truck drivers. A second questionnaire was used with management representatives of transport companies in the same state. No lit- erature review was reported. 1,249 truck drivers; 84 management representatives Heavy road transport industry Study relies on driver’s memories of their sleep and work activities as well as fatigue lev- els rather than objective measures. As a definition for fatigue was not provided for drivers or company representatives it is difficult to know how participants were interpreting this concept. In addition, comparisons with other studies must be viewed cautiously, since ques- tions and response options were not identical. 1. In a 24-hr period, approximately 38% of drivers exceeded 14 hr of driving and 51% exceeded 14 hr of driving plus other non-driving work 2. Approximately 17% of unregulated drivers exceeded 72 hr of driving in the week. When non-driving work was added, 30% worked in excess of 72 hr. 3. Approximately 12% of drivers reported less than 4 hr of sleep on 1 or more working days in the week preceding the interview. These drivers were likely to be operating their vehi- cles while having a significant sleep debt. 4. Approximately 20% of drivers who reported having less than 6 hr of sleep before start- ing their current journey reported 40% of the hazardous events. 5. Many drivers and company representatives reported fatigue to be a problem for other drivers but considered themselves or their companies’ drivers to be relatively unaffected by fatigue. 6. Nearly 70% of company representatives thought that long hours of driving were a main contributor of fatigue, while only 40% of drivers named long hours. About half the com- pany representatives thought lack of sleep contributed to fatigue while about one-third ARTICLE SUMMARIES Reviewers: Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings

of drivers thought so. Companies also identified inexperience as a cause of fatigue more often than did drivers. In contrast, more drivers blamed both loading the truck and delays in loading for their fatigue while fewer company representatives identified these two causes. 7. The authors concluded the paper by comparing their data on unregulated drivers’ per- ceptions about fatigue with those reported by Williamson et al. (1992) for mainly regu- lated drivers. The results suggest that unregulated drivers perceive fatigue to be a prob- lem for themselves less frequently than regulated drivers (10% versus 28 to 35%). Similarly, fewer unregulated drivers considered fatigue to be a general industry problem than did regulated drivers (39% versus 78%). These differences in frequency ratings may be due to differences in the attention paid to fatigue as a safety problem in regulated and unregulated states. In addition, it is possible that regulated drivers experience more fatigue because of long driving hours and less discretion to rest, than do the unregulated drivers. However, the authors caution that, in comparing the two studies, one must bear in mind that each asked different questions of drivers’ perceptions of fatigue and pro- vided different response options. Driver Fatigue/Alertness p. 476, “Twelve percent of drivers who reported having had a crash in the previous 9 months identified fatigue as a contributing factor.” p. 476, “. . . drivers appear to be over confident about their own resilience to fatigue even though they recognize that others are at risk of experiencing fatigue while driving.” p. 473, “Five percent of the unregulated drivers reported having experienced a hazardous, fatigue related event, such as nodding off, on their current journey.” p. 473, “. . . 20% of drivers who reported having had less than 6 hours sleep reported 40% of the hazardous events.” Driver Duration p. 472, “. . . 38% of drivers exceeded or would exceed 14 hours of driving in the 24 hour period. When other non-driving work was taken into account, the proportion exceeding 14 hours of work per 24 hour period increased by about 13%.” p. 472, “. . . 17.5% of unregulated drivers exceeded 72 hours of driving in the week. When non-driving work is added, 30% worked in excess of 72 hours.” Driver Health No significant findings or assumptions concerning impact on health. This paper was one of several in a special issue of the journal Accident Analysis & Pre- vention that focused on fatigue and transport. 56 Findings Directly Related to HOS (include page references): Reviewer’s Notes:

57 Dianne Davis, Alison Smiley Baas, P.H., Charlton, S., and Bastin, G. “Survey of New Zealand truck driver fatigue and fitness for duty.” (2000). 4th International Conference on Fatigue and Transportation, Fre- mantle, Western Australia. This paper summarizes the results of a survey of truck driver fatigue in New Zealand. Inter- views and performance tests were collected from truck drivers at various locations through- out the North Island of New Zealand throughout the day and night. In an analysis of the first 100 drivers, the researchers found that a sizable number of drivers exceeded the allowable driving hours. They also found high levels of fatigue and sleepiness and differences between line-haul and local delivery drivers. A survey was conducted with 600 truck drivers at depots, markets, and so forth around the North Island of New Zealand. Interviews focused on “driver demographic and work/rest patterns, drivers’ attitudes toward fatigue, propensity toward daytime sleepiness, and a self- assessment of drivers’ momentary level of fatigue. A simulator-based performance test of driving was also undertaken on an adapted version of the commercially available truck operator proficiency system (TOPS). “In the course of its development, TOPS passed through several verification and validation stages resulting in a pass/fail criterion for driver performance.” The performance test consisted of a standard driving task, a dual-axis sub- critical tracking task, and a tertiary or side-task requiring driver monitoring and periodic responses. “Calculation of pass/fail scores was based on five performance index coefficients (linear combinations of the performance variables). For each driver the five performance indices were calculated and compared to established performance criteria for each of the indices. The five indices, although composed of different weightings of the variables, can be characterized as focusing on the following five general categories: curvative error vari- ability, divided attention response time variability, throttle activity variability, steering activity variability, and longitudinal speed variability. A driver was required to obtain a passing score on each of the five performance indices in order to receive a passing score for the trial as a whole.” Interviews and simulator-based performance tests conducted at depots, wharves, markets, and other locations throughout the North Island of New Zealand throughout the day and night. 600 truck drivers ranging from 19 to 59 years of age (average age = 36; average years of experience = 13.76 years) Truck drivers (74% company employee drivers, 20% subcontractors, 4% working for owner/drivers, 2% independent owner/drivers) Study summarizes only initial results of the first 100 drivers. Selected performance indices are not necessarily valid predictors of crash risk. 1. “The drivers’ typical workday length ranged from 6 to 15 hr with an average across all drivers of 11.89 h and a S.D. of 1.683.” 2. “The average number of days driving per week ranged from 3 (relief and part-time driv- ers) to 7, with an average of 5.35 days, standard deviation of 0.557 days.” 3. Drivers typically rated fatigue to be a problem for other drivers more often than for themselves. 4. A much lower percentage of drivers rated fatigue as “never” being a problem for them than did drivers in Hartley et al.’s study (13% as opposed to 35.5% in Hartley et al.). 5. Large numbers of drivers did not comply with the HOS regulations. Reviewers: Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings

6. Drivers had an average of just 1.5 meals per day (0.5 of a meal was defined as a light snack, usually while driving). 7. The average Epworth Sleepiness Score of 7.53 (S.D. of 4.47) was substantially higher than the average score of 5.7 for truck drivers and 6.2 for automobile drivers reported in previous research (Maycock 1995). 8. Of all drivers, 91% passed all five performance criteria for the performance test on the simulator. “Of the 9% of drivers displaying driving performance below the criterion level, eight drivers failed the first performance criterion, a linear combination of mea- sures predominantly associated with curvature error variability.” 9. “Of the drivers’ activity and demographic measures, two were found to be particularly reliable predictors of simulator task performance: average distance driven per shift and driver age, F (2, 98) = 8.42, P < 0.01. Drivers with an average daily route of fewer than 250 km and drivers 37 years and older were much more likely to fail the performance test.” The authors noted that at this stage it was unclear “how to interpret the route length and age effects in the TOPS results.” Driver Fatigue/Alertness p. 188, Baas, “The drivers typically rated fatigue to be a problem for other drivers (21% rating it always or often a problem) more often than for themselves (8% rating it a prob- lem always or often).” p. 476, “The average Epworth Sleepiness Score of 7.53 (S.D. of 4.47) in our sample is sub- stantially higher than the average score of 5.7 for truck drivers and 6.2 for automobile driv- ers reported in previous research (Maycock 1995).” Driver Duration p. 188, Baas, “The drivers’ typical workday length ranged from 6 to 15 hr with an average across all drivers of 11.89 h and a S.D. of 1.683.” p. 188, Baas, “The average number of days driving per week ranged from 3 (relief and part- time drivers) to 7, with an average of 5.35 days, standard deviation of 0.557 days.” p. 188, Baas, “The results of the activity survey provide clear evidence that large numbers of drivers are not complying with the hours of service regulations” (i.e., no more than 11 hours on duty? Driving?, with at least 9 consecutive hours of rest between driving shifts. “ Thirty-three percent of drivers admitted to driving longer than 11 h in 24, and only 69% of drivers reported at least 9 consecutive hours of rest (9 hours sleeping plus hours relax- ing) between driving shifts.” Driver Health No significant findings or assumptions concerning impact on health. 58 Findings Directly Related to HOS (include page references):

59 Dianne Davis, Alison Smiley Balkin, T., Thome, D., Sing, H., Thomas, M., Redmond, D., Wesensten, N., Williams, J., Hall, S., and Belenky, G. (2000). “Effects of sleep schedules on commercial motor vehicle driver performance.” Department of Transportation, Federal Motor Carrier Safety Administration. FMCSA Tech Brief, 2000/09 (FMCSA-MCRT-00-015). “Effects of sleep schedules on commercial motor vehicle driver performance—Part 2.” N.B. In the summary of this study, not all direct quotes are indicated as such. A study was conducted to gather and analyze data on CMV driver rest and recovery cycles, effects of partial sleep deprivation, and prediction of subsequent performance. The project was composed of two studies. The first study was a field study using wrist actigraphy to determine sleep duration and timing in long- versus short-haul CMV drivers over 20 con- secutive days. The second study was a sleep dose/response (SDR) laboratory study on CMV drivers to determine the effects of 3, 5, 7 and 9 hr time in bed on performance (including simulated driving) over 7 consecutive days. The findings from the laboratory study were used to “optimize the parameters of the Walter Reed Sleep Performance model (SPM)—a mathematical algorithm to predict performance based on prior sleep and circadian rhythm. Field Study Study involved actigraphic assessment of sleep and driver/sleep logs, conducted with long- and short-haul CMV drivers over 20 consecutive days. The drivers wore the Walter Reed wrist actigraphs at all times except when bathing or showering. In addition they completed sleep logs on driver’s daily log sheets to gather subjective information about sleep times, sleep latency, arousals during sleep, alertness upon awakening, naps (number and duration), and self-reported caffeine, alcohol, and drug use. The data from each actigraph were downloaded to a personal computer, and each 24-hr actigraph recording period was examined for sleep in its entirety regardless of the duty status type or length indicated on the daily log sheet. Laboratory Study Primary objectives of the laboratory study were to “(1) determine the effects of four sleep/wake schedules on alertness and performance and (2) develop an algorithmic model to predict performance on the basis of prior sleep parameters.” Drivers had 3 days of ori- entation and baseline sleep in the laboratory before data collection commenced over 7 days of performance testing with 3, 5, 7, or 9 hr of sleep each night. The recovery period, that followed, lasted 4 days with 8 hr in bed each night. A wide variety of measures were used. Measures consisted of the psychomotor vigilance task (PVT), the cognitive performance assessment battery, driving simulator tasks (e.g., lane tracking) as well as sleep latency, EMG, and sleepiness ratings. In addition to these measures, a number of health measures were taken (e.g., tympanic temperature, heart rate, and blood pressure). Primary objectives of the laboratory study were to (1) determine the effects of four sleep/wake schedules on alertness and performance and (2) develop an algorithmic model to predict performance on the basis of prior sleep parameters.” Historical and methodological overview of sleep and performance, description of sleep/ performance model, field study using actigraphs, laboratory study of effect of sleep restric- tion on performance. Field Study: 50 long- and short-haul CMV drivers ages 21 to 65; Lab Study: 66 CMV driv- ers (16 females, media age = 43; 50 males, mean age = 37) Reviewers: Titles: Abstract: Methodology: Scope of Work: Sample Size:

Long- and short-haul driving Field Study • Actigraphy does not allow scoring of sleep stages, which may be differentially restorative. • The reliability of actigraphy in a moving motor vehicle (e.g., when a driver is sleep- ing in a sleeper berth of a moving vehicle) is currently unknown. • The reliability of subjective reports (e.g., subject logs) is typically low. • Two potential sources of error were uncovered during this study: – Time zones: Some drivers’ company work sites were in a time zone different from the time zone in which the driver resided. – Shifts to and from Daylight Saving Time (DST): Several drivers participated dur- ing shifts to or from DST. These shifts were reflected in the RODS (Driver’s Daily Log Sheets), but not in the actigraph data. These times had to be identified and the actigraph data adjusted to match the RODS. • The strength of this study is that all periods of sleep, not just those taken off-duty, were recorded for a large group of CMV drivers over an extended period of time. Laboratory Study • Study only looked at daytime driving. • Recovery sleep was restricted to 8 hr. • The trade-off for using a wide variety of measures was that the number of daily admin- istrations for each particular measure was restricted—precluding evaluation of circa- dian rhythms in this study. • Subjects were heterogeneous with respect to age, which may have contributed to error variance in performance measures. Field Study 1. Both long- and short-haul drivers averaged approximately 7.5 hr of sleep per night, which is within normal limits for adults. “However, the short-haul drivers tended to con- solidate their daily sleep into a single, off-duty period, whereas long-haul drivers obtained approximately half of their daily sleep total as daytime naps and/or during sleeper-berth time.” 2. As long-haul drivers obtained almost half of their daily sleep during work-shift hours (mainly sleep-berth time), it appears that they spend a significant portion of the work shift in a state of partial sleep deprivation, until the opportunity to obtain on-duty recov- ery sleep presents itself. 3. There was no off-duty duration that guaranteed adequate sleep for the long- or short- haul drivers. As drivers likely use a substantial portion of their off-duty time to attend to personal business, off-duty time must be of sufficient duration to allow drivers to accomplish these tasks and to obtain sufficient sleep. This may be particularly impor- tant for long-haul drivers, who often did not sleep at all during off-duty periods. 4. The bulk of the first (main) daily sleep bouts for short-haul drivers were initiated between 2000 and 0200. Sleep bouts initiated at these times lasted longer (i.e., clustered between 6 and 10 hr) than sleep bouts initiated at other times of day. Several of the sleep bouts initiated between these times lasted longer than 12 hr. 5. Similar to the short-haul drivers, the majority of long-haul drivers’ first sleep bouts were initiated between 2200 and 0359. However, long-haul drivers initiated their first sleep bouts more frequently during 0000 and 0359. The duration of long-haul drivers’ first sleep bouts clustered between 6 and 10 hr in duration. Sleep bouts exceeding 10 hr in duration 60 Industry Sector: Major Limitations: Findings

61 were uncommon and none exceeded 12 hr. Some sleep bouts were initiated in the early and late afternoon hours (1200 to 1959) and, unlike short-haul drivers, almost half of the first sleep bouts initiated during this time frame were longer than 4 hr in duration. 6. There were large day-to-day variations in total sleep time for drivers in both groups. Sleep times varied for some long- and short-haul drivers by up to 11.2 hr across the 20 study days for the long and short-haul drivers. Other drivers maintained more consistent sleep/wake schedules. Some showed a pattern that suggested chronic sleep restriction with intermittent bouts of extended recovery sleep. The authors felt that this suggested that although work-rest schedules could be devised to help minimize CMV driver sleep debt, optimal enhancement of driver alertness and performance would require additional and imaginative approaches. Laboratory Study 1. On average, subjects slept 2.9, 4.7, 6.3, and 7.9 hr for the 3-, 5-, 7-, and 9-hr time in bed conditions respectively, and displayed dose-dependent performance impairment related to partial sleep loss. (As can be deduced from these sleep times, as sleep restric- tion was more pronounced, sleep latency periods declined, resulting in greater sleep efficiency or proportionally more sleep in the available period.) 2. Performance in the 3-hr sleep group typically declined below baseline within 2 to 3 days of sleep restriction. 3. Performance in the 5-hr sleep group was consistently lower than performance in the 7- and 9-hr sleep groups. 4. Performance in the 7- and 9-hr sleep groups was often indistinguishable and improved throughout the study. However, the authors did note that “even a relatively small reduc- tion in average nighttime sleep duration (i.e., 6.3 hr of sleep—the average amount of sleep obtained by the 7-hr group) resulted in measurably poorer performance, for exam- ple, on the PVT. This decrement was maintained across the entire consecutive days of sleep restriction. 5. Virtually no negative effects on performance were seen in the 9-hr sleep group. 6. Sleep restriction effects were consistent. The degree to which “sleep restriction impaired performance was measure-specific.” “Across tasks, speed and throughput were con- sistently affected.” “In general, performance for the 3- and 5-hour sleep groups was below that of the 7- and 9-hour sleep groups.” “Thus, restricting sleep resulted in dose- dependent performance impairment.” 7. All cognitive tasks were sensitive to differential sleep restriction. 8. The PVT was the most sensitive measure. (It was also the performance measure which was the most resistant to changes in performance due to learning, an important issue when effects over many days are being examined.) Even the 7-hr group with 6.3 hr of sleep showed decreased performance using this measure across the 7 days. 9. The majority of driving performance measures (e.g., increased lane-tracking variabil- ity increased driving speed, increased speed variability, and increased running-off-road accidents) also showed dose-dependent and/or cumulative sleep restriction effects. 10. Following chronic sleep restriction, the first 8 hr in bed (6.5 hr of sleep) was insuffi- cient for restoration of performance on the PVT task. 11. During the 4-day recovery phase (8 hr in bed each night), 5- and 7-hr sleep groups showed minimal or no recovery, remaining consistently below the 9-hr sleep group and below their own baseline levels for the PVT. 12. The 3-hr sleep group showed some recovery for the PVT on the first day and more on subsequent days but also remained well below their own baseline and below the per- formance of the other groups. 13. Subjects’ recovery to baseline or near baseline levels of performance on the PVT often required a second or third night of recovery sleep.

14. These data suggest that after sleep debt has occurred (3, 5, 7 hr time in bed) a single bout of 8 hr of night sleep leads to recovery but not full recovery. While further sleep is required for full recovery, the number of subsequent sleep periods to reach full recov- ery is unknown. For the 3-hr group, the data suggests that even 3 nights of normal sleep (8 hr spent in bed on each night) is not sufficient to restore performance to baseline lev- els (depending on the task). This suggests that full recovery from substantial sleep debt requires recovery sleep of extended duration (i.e., more than 8 hr of normal-duration sleep). This is a unique finding and requires replication. 15. In contrast to the findings concerning PVT performance, the accident rate went back to baseline after 1 recovery day for all groups. In addition, lane position variability was near, but not quite back to baseline for all but the 9-hr group. On recovery days, lane position variability was slightly worse for the 9-hr group who, after being allowed 9 hr in bed each night during the work period, were restricted to 8 hr of sleep. 16. None of the physiological health measures (heart rate, blood pressure) evaluated in this study were sensitive to sleep restriction. 17. “Overall highest HR (collapsed across day and time of day) was seen in the 3-hr group (mean BPM = 79.74) and 7-hr sleep group (mean BPM = 78.64), while lowest HR was seen in the 9-hr sleep group (mean BPM = 70.46) and 5-hour sleep group (mean BPM = 75.48; group main effect, p < 0.05).” 18. “Across study days (collapsed across sleep group and time of day), highest HRs occurred across the last four days . . . while the lowest HR was observed on day E2.” 19. “Within days (collapsed across day and sleep group), the highest HR occurred at 1930 hours (mean BPM −79.87), whereas the lowest HR occurred at 1630 hours (mean BPM −72.60; time-of-day main effect, p < 0.05).” 20. Systolic blood pressure did not differ among sleep groups, nor did sleep group interact with day or time of day. 21. The highest systolic blood pressure (SBP) was found on day E4, the fourth experi- mental day, while the lowest SBP occurred on Day R2, the second recovery day. With respect to time of day, the highest SBP occurred at 1320, while the lowest SBP occurred at 0715. 22. “Diastolic pressure did not vary as a function of sleep group or day, nor did these fac- tors interact (main effects and interactions, ns).” 23. “Diastolic pressure varied across the day (time-of-day main effect, p < 0.05)—the high- est DBP values occurred at 0715 hours, and the lowest DBP occurred at 1025 hours. DBP values at 1320, 1625, and 1920 were intermediate between 0715 and 1025 hours and similar among each other.” Driver Sleep p. ES-5, Field Study: “. . . both long- and short-haul drivers averaged approximately 7.5 hours of sleep per night, which is within normal limits for adults.” p. ES-5, Field Study: “Time off-duty was positively correlated with total sleep time for both groups, but the short-haul drivers were more likely to consolidate their daily sleep into a single, work-shift sleep period.” p. ES-5, Field Study: “Long-haul drivers obtained almost half of their daily sleep during work-shift hours (mainly sleeper-berth time), which suggests that they spend a significant portion of the work shift in a state of partial sleep deprivation—i.e., until the opportunity to obtain on-duty recovery sleep presents itself.” p. ES-5, Field Study: “. . . there was no off-duty duration that guaranteed adequate sleep. . . .” p. ES-5, Field Study: “. . . large day-to-day variations in total sleep time were evident for drivers in both groups. . . .” 62 Findings Directly Related to HOS (include page references):

63 Driver Performance p. ES-8, Lab Study, “. . . even a relatively small reduction in average nighttime sleep dura- tion (i.e., 6.28 hours of sleep—the average amount of sleep obtained by the 7-hour group) resulted in measurably decremented performance (e.g., on the PVT). This decrement was maintained across the entire 7 consecutive days of sleep restriction, suggesting that there was no compensatory or adaptive response to even this mild degree of sleep loss.” p. ES-8, Lab Study, “. . . the extant level of daytime alertness and performance capacity is a function not only of an individual’s circadian rhythm, time since the last sleep period, and duration of the last sleep period, but is also a function of his/her sleep history, extending back for at least several days.” Driver Recovery p. ES-8, Lab Study, “. . . following more severe sleep restriction (e.g., the 3-hr group), recovery of performance was not complete after 3 consecutive nights of recovery sleep . . . this suggests that full recovery from substantial sleep debt requires recovery sleep of extended duration. Driver Health p. 2-88, Lab Study, “These results do not support the notion that physiological measures can serve as indices of subtle changes in cognitive performance capacity following sleep loss . . . To date, there is only limited evidence that sleep restriction, or sleep deprivation, affects physiological systems under involuntary control. In fact, none of the physiological health measures evaluated in this study (heart rate, respiration, and blood pressure) were sensitive to sleep restriction. These results also are consistent with the view that sleep depri- vation mainly impairs higher-order cognitive performance.”

Dianne Davis, Alison Smiley Dingus, T., Neale, V., Garness, S., Hanowski, R., Keisler, A., Lee, S., Perez, M., Robin- son, G., Belz, S., Casali, J., Pace-Schott, E., Stickgold, R., and Hobson, J.A., The Impact of Sleeper Berth Usage on Driver Fatigue. FMCSA, FMCSA-RT-02-050, Washington, DC, November 2001. Federal Motor Carrier Safety Administration. “Impact of sleeper berth usage on driver fatigue: Final Report.” (2002). Report Number: FMCSA-RT-02-070. Klauer, S.G., Dingus, T.A., Neale, V.L. and Carroll, R.J. (2003) “The effects of fatigue on driver performance for single and team long-haul truck drivers.” Driving Assessment 2003—The Second International Driving Symposium on Human Factors in Driver Assess- ment, Training and Vehicle Design. Park City, Utah. N.B. All quotes are from FMCSA summary. This report documents research that was conducted on sleeper-berth usage. In addition to focus groups with long-haul operators, a field study was conducted on sleeper-berth usage for single and team drivers. The report outlines a number of factors, discovered in the focus groups, which are important to successful sleeper-berth usage for single and team drivers. Based on the results of the focus group and an accompanying literature review the researchers designed an on-road study with 56 drivers (47 male, 9 female; mean age = 42.6) constituting 13 teams and 30 single drivers to assess the effects of sleeper-berth usage on sleep, driver error, and critical incidents. Focus Groups: Ten focus groups were conducted in 8 cities, across 7 states. Field Study: Long-haul truck drivers operated heavy trucks for a minimum of 6 continuous days, with the typical run being 7 to 10 working days, on their regularly assigned route. Data collec- tion systems were installed on the tractors used by the drivers to collect sleeper-berth envi- ronmental data, driving performance information, video of the driver’s face, and subjective alertness ratings and data from the Nightcap sleep system. Data (i.e., computer and video) were collected before and during critical incidents such as lane and steering deviations. Based on the findings of the focus groups and a literature review, a field study protocol was developed to assess the impact of sleeper berth usage. The field study was designed to deter- mine relationships between sleep quality, driver alertness, and driving performance. Focus Groups: 74 participants (27 to 70 years of age). Field Study: 56 drivers participated in the field study (30 single drivers and 13 teams of driv- ers; 7 females, 49 males; mean age = 42.6). Long-haul operators n/a Focus Groups 1. “Team versus single driving was identified as a very important factor for drivers relat- ing to quality of sleep.” Drivers either loved or hated team driving and discussed vari- ous issues relevant to their preference (e.g., trust, partner’s driving ability, driving smoothly, etc.). Drivers also discussed various equipment issues with respect to com- fortable sleeping arrangements (e.g., noise, air-ride vs. spring-ride trucks, etc.). 64 Reviewers: Titles: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings

65 Field Study: Team Driving vs. Single Driving 2. Single drivers were involved in significantly more critical incidences than team drivers. They were involved in “four times the instances of “very/extremely drowsy” observer ratings than were team drivers, and were more likely to push themselves to drive on occasions when they were very tired.” 3. More than one-half of the most severe of the critical incidents were caused by 4 of the 30 single drivers. In contrast, team drivers were generally very successful at avoiding circumstances of extreme drowsiness, drove much less aggressively, and made fewer errors than single drivers. 4. The main effect for segment of day was significant (p < 0.05). Team drivers tended to exhibit critical incidents associated with extreme fatigue during the morning and night hours (morning: 0400 to 1159; afternoon: 1200 to 1759; night: 2200 to 0359). Single drivers “tended to show fewer extreme fatigue-related critical incidents during the morn- ing hours, with gradually more critical incidents being attributed to the very drowsy cat- egories during the evening and nighttime hours.” The authors note that single drivers “were exhibiting signs of extreme fatigue during all hours of the day while team drivers only showed signs of fatigue during the nighttime and morning hours.” 5. Overall, team drivers were able to better manage their fatigue and critical incident involvement than were single drivers. This may be because team drivers are more likely to effectively trade-off driving duties with their partner before to becoming extremely fatigued. It is also possible that in effect, drivers undergo a natural “screening” process. Focus group participants noted that team drivers must be trustworthy with regard to their driving ability and be considerate of their resting partner. Field Study: Quality of Sleep 6. A number of findings indicated that the quality and depth of sleep was worse (e.g., more sleep disturbances) on the road, particularly for team drivers. They found that while the vehicle was in motion, the noise and motion environment in the sleeper berth degraded the drivers’ sleep. Field Study: Hours of Service 7. “In terms of hours of service violations, based on a report by Wylie et al. (1996), there were relatively few instances (about 2.2%) of “extreme drowsiness,” with most of these instances being experienced by single drivers, again with a high rate of the occurrence of this level of fatigue on the second or third shift after the first day of a multi-day drive.” There were relatively few instances of “extreme drowsiness” (2.2%), with most of these instances being experienced by single drivers, with a high rate of the occurrence of this level of fatigue on the second or third shift after the first day of a multi-day drive.” 8. The authors note that it “appears that the combination of long driving times and multi- ple days provides the greatest concern, with several results pointing to the presence of cumulative fatigue.” As a result they believe that the length of shifts in the later stages of a trip must also be considered. However, the authors point out that “critical incidents and/or driver errors did not increase directly with the hours beyond the regulation,” and that “there was a substantial decrease in the rate of critical incidents during some of the more extreme violations.” However, they do caution that this should not be interpreted to mean that HOS should be expanded due to the following two reasons: “First, it may be possible that the drivers were making a point to drive more carefully and cautiously because they were operating outside of the regulation and did not want to get stopped by law enforcement officials. Alternatively, they may have only risked driving outside of the regulations because they felt alert and knew that they could continue to drive safely.”

Driver Fatigue/Alertness p. 3 Tech Report FMCSA-RT-02-070, “. . . team drivers were generally very successful at avoiding circumstances of extreme drowsiness. Conversely, single drivers were greatly affected by drowsiness, which in turn, compromised their ability to safely operate their vehicles.” p. 3 Tech Report FMCSA-RT-02-070, “. . . team drivers appeared to drive much less aggressively, make fewer errors, and rely effectively on their relief drivers to avoid instances of extreme drowsiness while driving.” p. 4 Tech Report FMCSA-RT-07-070, “. . . single drivers in this study had many more criti- cal incidents at all levels of severity as compared to team drivers. Single drivers were involved in four times the instances of “very/extremely drowsy” observer ratings than were team driv- ers, and were more likely to push themselves to drive on occasions when they were very tired. In fact, in looking at only the most severe of the critical incidents, more than one-half of the incidents were actually caused by four single drivers.” Driver Duration p. 4 Tech Report FMCSA-RT-07-070, “In terms of hours-of-service violations, based on a report by Wylie et al. (1996), there were relatively few instances (about 2.2%) of “extreme drowsiness,” with most of these instances being experienced by single drivers, again with a high rate of the occurrence of this level of fatigue on the second or third shift after the first day of a multi-day drive. Thus it appears that the combination of long driving times and multiple days provides the greatest concern, with several results pointing to the pres- ence of cumulative fatigue. This means that the length of shifts in the later stages of a trip must also be carefully considered.” Driver Health No significant findings or assumptions concerning impact on health. 66 Findings Directly Related to HOS (include page references):

67 Dianne Davis, Alison Smiley Feyer, A.M., Williamson, A., and Friswell, R. “Balancing work and rest to combat driver fatigue: An investigation of two-up driving in Australia.” (1997). Accident Analysis & Pre- vention, 29 (4) 541–53. This study was designed to examine the “nature and impact of two-up driving operations on fatigue.” Long-haul truck drivers were measured on a 4,500-km round trip. The driving operations of single driving (i.e., a solo driver) and two-up driving (i.e., pair of drivers oper- ating a truck continuously, alternating work and rest) were compared. “A between groups design was used for this study, in which each participant only drove one evaluated trip using his regular operation—either two-up or single.” Drivers were asked to drive a 4- to 5-day round trip of approximately 4,500 km in Western Australia. At the time of the study, the state of Western Australia did not have enforced driving hours regulations. Twenty-two of the 37 participants regularly worked two-up operations on the selected route and 15 regularly worked as single drivers. A variety of measures were used to assess drivers’ fatigue and its effects such as heart activity, speed and steering wheel angles, auditory reac- tion time tasks, cognitive tests, and subjective measures of fatigue. Prior to starting their trip, participants were also asked to complete questionnaires about their general state of physical health, their lifestyle, and their pattern of work-rest in the week preceding the study. Field study of single versus team drivers conducted in Western Australia. 37 male professional long-distance drivers (average age = 37; average of 13 to 15 years of commercial driving experience) Professional long-distance drivers The state of fatigue of the two groups being compared, two-up and single drivers, was not equivalent at the start of the study. 1. “Irrespective of driver operation, fatigue increased for drivers on long-distance trips typ- ical of remote zone driving.” 2. “Two-up drivers reported and showed evidence of greater fatigue than single drivers before the trip started and appeared to be more fatigued overall for most of the trip.” 3. “Over the homeward leg of the trip, two-up drivers reported no change in the level of fatigue, with fatigue having peaked at mid trip. For single drivers, in contrast, fatigue peaked at the end of the homeward leg, despite considerable recovery at mid trip.” 4. While overall the two-up group showed greater fatigue compared with single drivers, some ways of doing two-up (e.g., overnight stationary rest, shorter trip duration) were less fatiguing than single driving. 5. Two-up drivers started the trip more fatigued and this “disadvantage remained for most of the trip” . . . “but was most marked over the first leg of the trip where fatigue for two- up drivers continued to worsen at a greater rate than for single drivers.” 6. “. . . where work practices kept the fatigue under control, such as on shorter two-up trips and two-up trips incorporating overnight stationary rest, breaks were more likely to be helpful. In contrast, where fatigue was allowed to build-up, such as on single trips and on very long two-up trips without stationary rest, breaks did not provide relief once fatigue had accumulated.” Driver Fatigue/Alertness p. 550, “Overall, the heart rate measures confirmed earlier findings that single drivers were more alert than two-up drivers at the start of the trip.” Reviewers: Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Findings Directly Related to HOS (include page references):

p. 552, “Two-up drivers reported and showed evidence of greater fatigue than single driv- ers before the trip started and appeared to be more fatigued overall for most of the trip.” p. 552, “Over the homeward leg of the trip, two-up drivers reported no change in the level of fatigue, with fatigue having peaked at mid trip. For single drivers, in contrast, fatigue peaked at the end of the homeward leg, despite considerable recovery at mid trip.” p. 552, “Overnight stationary rest for two-up drivers at mid trip, was associated with dra- matic reductions in fatigue levels after the break, and allowed these drivers to finish the trip with the lowest levels of fatigue of any group, including single drivers.” p. 552 “Two-up drivers who had no stationary rest, but had the shortest trip duration of any group, showed an overall increase in alertness over the homeward journey, finishing the trip at roughly pre trip fatigue levels.” Driver Duration p. 553, “Working hours regulations for long distance drivers are primarily based on limi- tations to periods of driving and rest within a trip, largely in isolation from overall sched- uling patterns. In contrast, the current findings strongly suggest that effective management of fatigue involves considerations of the whole pattern and timing of work and rest . . .” Driver Health No significant findings or assumptions concerning impact on health. 68

69 Dianne Davis, Alison Smiley Gillberg, M., Kecklund, G., and Akerstedt, T. (1996). “Sleepiness and performance of pro- fessional drivers in a truck simulator—comparisons between day and night driving.” Jour- nal of Sleep Research, 5, 12–15. This paper summarizes a study comparing daytime and nighttime performance of profes- sional drivers on a simulated driving task. The authors noted that to their knowledge no studies had been conducted reporting on the effects of sleepiness on night driving perfor- mance in a dynamic truck simulator using professional drivers as subjects. The secondary purpose of the study was to test whether a nap, or a rest pause, would affect performance. Nine professional drivers participated 4 times in a counterbalanced repeated measures design. “The conditions were day driving (DAYDRIVE), night driving (NIGHTDRIVE), night driving with a 30-min rest (NIGHTREST), and night driving with a 30-min nap (NIGHTNAP).” Time of day was not specified. “Each condition consisted of three consec- utive 30-min periods.” The 30-min duration of each period was an adaptation to the maxi- mal continuous driving period allowed by the simulator software. “For the DAYDRIVE and NIGHTDRIVE all periods were spent driving while the second period was either a rest pause or a nap for the other two conditions.” “Mean speed, standard deviation of speed, and stan- dard deviation for lane position were recorded. Self ratings of sleepiness (e.g., Karolinska Sleepiness Scale) were obtained before and after each 30-min period. Reaction time tests and 10-min standardized EEG/EOG recordings were obtained before and after each con- dition.” Electroencephalogram/electro-oculogram (EEG/EOG) recordings were obtained before and after each condition. EEG/EOG were also recorded continuously during driving. Simulator study Nine professional drivers (mean age: 42 years, range 28 to 55 years; mean professional experience: 17 years; mean experience of night work: 8 years). Professional truck drivers Relatively short task (continuous driving for only 30 min at a time), with a maximum of 1.5 hr of driving, on a simulator. 1. The authors noted that despite the relatively short task (continuously driving for only 30 min at a time) differences between day and night driving performance could be demonstrated. The effects on driving were small but significant: night driving was slower, with a higher variability of speed, and higher variability of lane position. 2. Subjective and EEG/EOG sleepiness were clearly higher during the night conditions. 3. Reaction time performance was not significantly affected by conditions. 4. The authors noted that the task per se affected alertness, as indicated by the clear increase in subjective and electrophysiological sleepiness as well as in reaction times over the three periods even for the day driving condition. 5. Neither the nap nor the rest pause had any effect. The authors note that a nap of the same duration during the day, on the other hand, has been shown to have clear positive effects. They felt that as sleep inertia tends to be more pronounced with the longer wake times that will precede night naps (Dinges 1985), this might have obscured the possible posi- tive effects of the nap in the present experiment. It is clear, however, that the nap did not have a negative effect which could have been the result if severe sleep inertia had occurred. The authors conclude that the most reasonable explanation to the lack of nap effect is that it was too short to counteract the low levels of alertness during the circa- dian trough after an extended time awake. Reviewers: Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings

Driver Fatigue/Alertness p. 14, “Sleepiness ratings: These were significantly (F = 20.6; P = 0.0001) higher during the night conditions compared to the day (DAYDRIVE 4.3 < NIGHTDRIVE 6.0; NIGHT- CAP 5.7; NIGHTREST 5.5).” p. 14, “The level of sleepiness increased significantly (ANOVA) across the three 30-min periods (F1,8 = 27.8; P = 0.0008; changes from before period ‘a’ to after period ‘c’” DAY- DRIVE 3.3–5.6; NIGHTDRIVE 5.1–7.2; NIGHTNAP 4.0–7.1; NIGHTREST 4.4–6.7). p. 473, “Mean percentage of time with sleepiness differed significantly between the day and night driving conditions (F = 4.8; P = 0.0453; DAYDRIVE 29.6 < NIGHTDRIVE 43.6; NIGHTNAP 33.2; NIGHTREST 41.9).” Driver Skill p. 13, “. . . when contrasting only the last 30-min periods the mean speed was significantly higher during the day compared to the three night conditions.” p. 13, “. . . speed variation during period ‘c’ was significantly lower during the day drive compared to the three night conditions .” p. 13, “. . . for period ‘c’ the lane position varied significantly less during the day .” Driver Health No significant findings or assumptions concerning impact on health. 70 Findings Directly Related to HOS (include page references):

71 Dianne Davis, Alison Smiley Hakkanen, H. and Summala, H. (2002). “Driver sleepiness-related problems, health status, and prolonged driving among professional heavy-vehicle drivers.” Transportation Human Factors, 2(2), 151–171. This paper summarizes the results of a survey conducted with 567 Finnish professional driv- ers, with 5 different work descriptions, who were part of a nonpolitical organization pro- moting truck drivers’ interests. The mailed questionnaires were completed anonymously. “The main purpose of this survey study was to examine the relation between truck drivers’ health and sleepiness-related problems while driving. In addition, factors most likely to pre- dict increased driver sleepiness were identified. Furthermore, frequency of non-compliance with the driving-hours regulations (in terms of driving more than 10 hr) and drivers’ com- prehension regarding the suitability of the regulation were surveyed.” “In Finland, truck driving hours are subject to control by EC regulation No. 3820/85, according to which the maximum driving time is 10 hr and the resting time is 11 hr per each 24-hr period.” Previ- ous studies had indicated that all drivers do not follow the limits set by the regulation. A questionnaire was sent to “2,000 randomly chosen members of a nonpolitical organiza- tion promoting truck drivers’ interests (16,508 members in all).” A total of 567 usable ques- tionnaires were returned. The questionnaire contained questions on individual characteris- tics, their preceding 3 months’ work, possible sleepiness-related problems at work and their opinions about maximum permitted driving times. In addition, they were also given parts of the Basic Nordic Sleep Questionnaire and the Epworth Sleepiness Scale to estimate the “prevalence of suspected sleep apnea syndrome and to collect data of driver’s sleep his- tory.” Drivers were also asked questions about their self-perceived general health status and the occurrence of any chronic illnesses. Questionnaire distributed to 2,000 professional drivers in Finland. 567 drivers (long-haul drivers = 44%; short-haul drivers = 25%; drivers transporting dan- gerous goods = 16%; drivers transporting wood = 8%; bus drivers = 7%) Professional drivers Study relies on driver’s memories of their sleep and work activities as well as fatigue levels rather than objective measures. Screen for sleep apnea only took place through questionnaires. 1. “The results of the study indicated that approximately one-third of all the drivers drive generally more than 10 hr, which violates the EC regulation.” 2. “More than 70% of the drivers felt that the maximum permitted driving hours should be at least 11 hr per a 24-hr period.” 3. Nineteen percent reported having dozed off at least twice while driving, and 8% reported a near-miss situation due to dozing off during the past 3 months. 4. “Sleepiness-related problems while driving appeared across all driver groups (i.e., long haul, short haul, bus drivers, drivers transporting dangerous goods, drivers transport- ing wood), including drivers transporting dangerous goods and bus drivers, and were strongly related to prolonged driving, sleep deficit and drivers’ health status.” The effects of the latter factors were interactive and cumulative: Frequent sleepiness-related problems occurred in more than one half (52.3%) of the “drivers with the combination of prolonged driving, sleep deficit, and lowered self-perceived health.” 5. The 10% of drivers who were suspected to have sleep apnea syndrome (note: screen- ing through questionnaires only) reported having experienced significantly more fre- quent sleepiness-related problems while driving although they did not report a signifi- cant increase in the frequency of sleepiness-related accidents. Reviewers: Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings

6. Thirty-one percent of the drivers perceived their general health status to be no more than satisfactory. 7. Drivers who reported their health status to be no more than satisfactory were ”signifi- cantly older, reported driving for longer hours, had experienced more frequent diffi- culties in remaining alert, dozing off, and following near-miss situations while driving, as well as accidents at work due to dozing off.” 8. A significantly higher percentage of those drivers who perceived their health as satis- factory as compared with those rating it at least good, reported driving generally more than 10 hr (12% vs. 5%). 9. “A significantly higher proportion of drivers with no more than satisfactory health also had more than a 1-hr average sleep deficit, compared to drivers with self-perceived good or excellent health (29% vs. 13%).” 10. Twenty-five percent reported having detected a chronic illness during the past 3 years. Drivers with an illness were “significantly older, had been driving for longer hours, reported more frequent difficulties in remaining alert and dozing off while driving.” A significantly higher percentage of these drivers reported driving generally more than 10 hr than drivers with no illness (11% vs. 6%). In addition, “of the drivers with an ill- ness 23% had more than a 1-hr average sleep deficit compared to 17% of drivers with no illness.” 11. According to the authors, the connection between a chronic illness and sleepiness- related problems while driving was somewhat mixed. While “the univariate comparison between those with an illness and others suggested a marked difference in sleepiness- related problems,” the “logistic regression analysis showed that when other relevant factors were controlled (e.g., age, driving time) the effect of a chronic illness was no more significant whereas perceived health status better explained sleepiness-related problems while driving.” They suggested that this result might be partly due to the fact that the discovered illnesses were rather heterogeneous. “Further concern is raised by the results that nearly one fourth of the drivers with an illness had sleep deficit. In addi- tion, compared to the drivers with no illness, prolonged driving was more common among drivers with a chronic illness.” 12. Increased odds of having more frequent difficulties in remaining alert if the driver self- perceived as having no more than satisfactory health. 13. The authors conclude that the results give unreserved support for regulating driving hours and increase concern of the connection between professional drivers’ health sta- tus and sleepiness-related problems while driving. 14. Drivers were more apt to have frequent difficulties remaining alert if they had been driv- ing a night or irregular shift, or had been driving more than 17 hr. Driver Fatigue/Alertness p. 169, “The results indicate that to a certain degree sleepiness-related problems while driv- ing seem to be associated with the interactive effect of prolonged driving, sleep deficit, and subjective health status. After all, frequent sleepiness-related problems were substantially more common among drivers with the combination of no more than a satisfactory health, prolonged driving, as well as sleep deficit. Notably, frequent difficulties in remaining alert and dozing off had occurred in more than one half of these drivers whereas in only approx- imately 10% of those drivers with a driving time of at most 10 hr, no sleep deficit, and at least a good health. Therefore, restricting driving hours may in fact help to improve occu- pational health as well as traffic safety.” p. 169, “. . . the analysis indicated that prolonged driving (in terms of driving more than the permitted driving hours set by the EC regulation) is indeed associated to sleepiness- related problems while driving whether they be difficulties in remaining alert, dozing off, or near-miss situations and that difficulties in remaining alert are associated with driving a night or irregular shift.” 72 Findings Directly Related to HOS (include page references):

73 p. 162, “. . . when all the relevant factors were controlled, shift type and driving time were the only work-related variables that significantly predicted more frequent difficulties in remaining alert (p < .05 and p < .05, respectively). The odds of having experienced more frequent difficulties increased by a factor of 1.85 if the driver had been driving a night or irregular shift and by 3.57 if the driver had been driving more than 17 hr (compared to fewer than 6 hr driving).” Driver Duration p. 166, “. . . approximately one third of all the drivers drive generally more than 10 hr, which violates the EC regulation.” p. 166, “More than 70% of the drivers felt that the maximum permitted driving hours should be at least 11 hr per a 24-hr period.” Driver Health p. 169, “ The univariate comparison between those with an illness and others suggested a marked difference in sleepiness-related problems, but the “logistic regression analysis showed that when other relevant factors were controlled (e.g., age, driving time) the effect of a chronic illness was no more significant whereas perceived health status better explained sleepiness-related problems while driving.” “p. 169 “. . . the analysis indicated that the effect of suspected sleep apnea syndrome on sleepiness-related problems while driving was significant when predicting dozing off.” p. 169, “. . . an important result of the logistic regression analysis is that of increased odds of having more frequent difficulties in remaining alert if the driver self-perceived as hav- ing no more than a satisfactory health.”

Dianne Davis, Alison Smiley Hanowski, R. J., Wierwille, W. W., Gellatly, A. W., Early, N., and Dingus, T. A. (2000). “Impact of local short-haul operations on driver fatigue.” Department of Transportation Federal Motor Carrier Safety Administration. This paper summarizes the results of an on-road field study focusing on the fatigue experi- enced by local/short-haul truck (L/SH) drivers (i.e., trips less than 100 mi from home base) on typical workdays, whose vehicles were instrumented with data collection equipment. Forty-two male L/SH drivers (mean age = 31) participated in the study. Drivers completed 2 weeks of Monday-Friday daytime driving on normal delivery routes that were within 100 mi of home. Their distribution of work consisted of driving (28%), loading/unloading (35%), other assignments (26%), waiting to unload (7%), eating (2%), resting (0.5%) and other activities (1.5%). The authors used subjective, objective, and physiological measures to assess fatigue, inat- tention, and drowsiness. Subjective measures included self-report on levels of stress. Objec- tive measures included the degree of eyelid closure. Physiological measures included indi- cations of sleep quantity and quality as collected by wrist activity monitors. In addition the “black box” data collection equipment installed in the truck collected driver performance associated with “critical incidents,” (i.e., near-crash events). Several small video cameras were used to monitor each truck driver and surrounding traffic situation, and sensors col- lected data from the vehicle’s instruments. The authors conducted analyses of videotape of the 3-min interval preceding the start of a critical incident. An incident was defined as a control movement exceeding a threshold based on driver or analyst input. Analysts recorded eye transitions and the proportion of time that the driver’s eyes were closed/nearly closed, or off the road, during these 3-min intervals. On-road field study where L/SH trucks were instrumented with data collection equipment. As a precursor to this research, the authors had conducted a series of focus groups in which L/SH drivers provided their perspective on safety issues, including fatigue, in their indus- try. (The results of these discussions are summarized in publication no. FHWA-MCRT-99- 002). The authors propose five guidelines aimed at reducing critical incidents that are caused by L/SH drivers. 42 local and short-haul drivers (mean age = 31); 30 drivers from the beverage company and 12 drivers from the snack food company) Local and short-haul truck driving Only daytime driving was considered. Amount of last recovery time before starting the study was unknown. 1. Over the 2-week period, there were 77 incidents (average 1.8 per driver) where the driver was judged to be at fault. 2. Inattention was thought to be involved in 57 critical incidents and fatigue a contribu- tor to 28 critical incidents (i.e., 20.8% of incidents where the L/SH driver was judged to be at fault). 3. The majority of the L/SH driver at fault critical incidents were caused by about one- quarter of the drivers. 4. Ten of the 42 drivers were involved in 86% of the incidents. 5. The younger and less experienced drivers were significantly more likely to be involved in critical incidents and exhibited higher on the job drowsiness. 6. “Drivers tended to be involved in fatigue-related incidents earlier in the workweek. There were no fatigue-related critical incidents after the fourth day of the workweek.” 7. The highest frequency of driver-at-fault incidents was between noon and 1:00 p.m. The increase in incidents during these periods may be attributed to increased exposure. 74 Reviewers: Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings

75 8. During the study, the drivers’ mean sleep was 6.43 hr per night (sleep log) and 5.31 hr based on the Actiwatch (developed by Mini Mitter Co., Inc.). 9. Data was divided into two groups where fatigue was apparent or not apparent. “To clas- sify incidents into one of these two groups, threshold values for PERCLOS and OBSERV were set such that fatigued drivers were defined as having PERCLOS greater than or equal to 0/08 or an OBSERV value greater than or equal to 40. If an event did not meet one of these criteria, then the driver was deemed to be ‘not fatigued.’” Drivers who showed evidence of fatigue and were involved in fatigue related incidents had less sleep and poorer quality sleep than drivers who did not show signs of fatigue. The drivers from the beverage company typically worked 10 to 11 hr per workday. The snack food drivers worked roughly 12 hr per workday. The majority of drivers worked 5 days per week. 10. The self-reported amount of sleep and quality of sleep for the night before the incident were less when the driver was categorized as being fatigued. Drivers in the fatigue group had 5.33 hr of sleep compared with 6.13 hr in the no-fatigue group. 11. “. . . much of the fatigue that the drivers’ experienced was brought with them to the job, rather than being caused by the job.” The authors concluded that off-duty behavior was the “primary contributing factor in the level of fatigue that was demonstrated during the workday.” 12. Drivers in the fatigue group spent more hours driving during the day of the critical inci- dent as compared with drivers in the no-fatigue group. Driver Fatigue/Alertness p. 155, “drivers demonstrated, to a statistically significant level, signs of fatigue for a time period immediately preceding incident involvement where the L/SH driver was judged to be at fault. p. 155, “. . . fatigue does appear to be an issue in L/SH trucking operations. Because this was a field study, it is difficult to determine with certainty why fatigue was present.” p. 155, “. . . based on the results of the multiple analyses that were conducted, it seems apparent that much of the fatigue that the drivers’ experienced was brought with them to the job, rather than being caused by the job. That is, poor sleep quantity/quality were prominent for drivers who demonstrated signs of fatigue on the job. Therefore, it is sug- gested that the off-duty behavior of the drivers was the primary contributing factor in the level of fatigue that was demonstrated during the workday.” p. 99, “. . . the highest frequency of driver-at-fault incidents was between noon and 1 PM . . . Potential explanations for this finding are that the L/SH drivers may be experiencing drowsiness after eating lunch, or that eating-while-driving, a common observance with the drivers in this study, may have drawn attention away from the driving task.” Driver Duration p. 77, “The total shift time shows that both groups of drivers from the beverage company typically worked 10 to 11 hours per workday, while the snack food drivers worked roughly 12 hours per workday. The majority of drivers worked five days per week.” p. 112, “. . . drivers in the fatigue group spent more hours driving during the day of the crit- ical incident (M = 4.38) as compared to drivers in the no-fatigue group (M = 3.43). Driver Health No significant findings or assumptions concerning impact on health. Findings Directly Related to HOS (include page references):

Dianne Davis, Alison Smiley O’Neill, T.R., Krueger, G.P., Van Hemel, S.B., and McGowan, A.L. (1999). “Effects of operating practices on commercial driver alertness.” Rep. No. FHWA-MC-99-140, Office of Motor Carrier and Highway Safety, Federal Highway Administration, Washington, D.C. O’Neill, T.R., Krueger, G.P., Van Hemel, S.B., McGowan, A.L. and Rogers, W.C. (1999). “Effects of cargo loading and unloading on truck driver alertness.” Transportation Research Record 1686, TRB, Washington, D.C. pp. 42–48. Rogers, W. (2000). “Effects of operating practices on commercial driver alertness.” Pro- ceedings of the Conference Traffic Safety on Two Continents held in Malmo, Sweden, Sep- tember 20–22, 1999. Tech Brief (1999). (FHWA-MCRT-99-008) “Effects of operating practices on commercial driver alertness.” This project consisted of focus groups, a driver survey, and interviews with CMV drivers focused on the physical requirements (loading/unloading) across the industry. This was fol- lowed by a driving simulator study which investigated “fatigue-related decline in driving performance resulting from loading and unloading cargo,” “non-duty time (rest and recov- ery) required to reestablish baseline fitness for duty,” and “driver performance under a sus- tained 14 hours on/10 hours off schedule. Researchers examined driver performance over a 15-day period.” Ten male CMV drivers operated a “driving simulator in simulated long- haul runs for a period of 15 days, including occasional loading/unloading sessions and a relatively high frequency of simulated crash-likely events.” Performance measures and measures of subjective drowsiness were collected. In addition, participants wore wrist activity monitors to assess the amount of sleep. “The effects of loading and unloading task were mixed. There was an initial improvement in alertness; however, this effect wore off as the day progressed and may have contributed to a decrease in overall performance after 12 to 14 h of duty.” “Drivers recovered baseline performance within 24 hours of the end of a driving week and should be fit to resume duty after 36 hours.” “A schedule of 14 hours on duty/10 hours off duty for a 5-day week did not appear to produce cumulative fatigue.” The experiment used a mixed between-and-within-subjects design that required each of the 10 truck driver subjects to operate a simulator in simulated long-haul runs for a period of 15 days, including occasional loading/unloading sessions and a relatively high frequency of simulated crash-like events (e.g., 8 events in a 12-hr day). The complete test cycle for each driver required 17 days: • Days 1–2: Simulator and procedural familiarization • Days 3–7: Week 1 of driving operations • Days 8–9: Recovery time (58 hr off duty) • Days 10–14: Week 2 of driving operations • Days 15–16: Recovery time (58 hr off duty) • Day 17: Final driving day to verify performance recovery Drivers were screened for undiagnosed sleep disorders and to verify that the driver began the test period nominally rested by examining the records from a wrist activity monitor for the 48 hr preceding the start of the experiment and the 2-day familiarization period. The authors did not mention that any drivers were disqualified for sleeping disorders. Drivers were held to a schedule of 14 hr on duty (12 hr driving plus scheduled breaks) fol- lowed by 10 hr off duty. The daily driving schedule ran from simulator engine start at 0700 to shutdown at 2100. Breaks were taken on the experimental schedule and not at the subject’s 76 Reviewers: Titles: Abstract: Methodology:

77 discretion (30-min break at 1000, a 45-min lunch break at 1345, and a 30-min break at 1730). During week one of driving, half of the drivers conducted simulated loading/unloading oper- ations for 3 days and no loading/unloading operations in week 2. The remaining drivers did the reverse (i.e., loaded in week 2). On loading days, drivers performed two 90-min loading/ unloading sessions during the driving day, one in the morning and one in the afternoon. Drivers wore wrist actigraphs for 48 hr preceding the start of the experiment to establish a rested state at the beginning of the experiment and to observe the driver’s habitual sleep habits. The Stanford Sleepiness Scale, driver subjective ratings of tiredness, were adminis- tered at the end of each driving or loading/unloading period. The drivers were housed in an apartment near the test site but were not confined to the apartment or physically monitored during the duty week. Drivers were instructed to get a good night’s sleep each night at the apartment. Actual sleep was verified by wrist actigraphy. During recovery days, the driver remained in his lodging. Drivers were allowed to leave the residence area for short trips to eat, exercise, or perform other normal activities. During 90-min scheduled driving periods, performance measures were maintained and recorded and compiled into 10-sec time periods. Driving performance measures were drawn from built-in parameters associated with the simulator (FAAC DTS-2000) plus computer generated video imagers of driver appearance. The simulator database includes 87 mi of varied highway, including urban and rural roads, divided highway, and primary and sec- ondary road. Urban areas include buildings. (Note: Authors did not describe which types of roads were used in testing.) Driving runs were conducted using 12 preset scenarios, each consisting of a fixed route designed to take approximately 90 min to complete at the posted speed limits. The DTS-2000 measures included lane position, shifting performance, brake usage, and response probes (e.g., psychomotor response time to driving computer-mediated scenarios). Response probes (e.g., traffic stop, lane cross, etc.,) were used as a primary measure of driver performance (and represent a departure from typical studies of this type) and provided tests of driver vigi- lance, alertness, and response time. Driver response was evaluated by expert trainers based on a three-point scale. During driving days a Psychomotor Vigilance Task (PVT) was administered 3 times (0645, 1330, and 2100). Subjective examination of video records of drivers during simulated oper- ations were conducted for samples taken from periods during which parallel indicators showed evidence of good or poor performance. Multiple measures were employed to gauge recovery, including sleep patterns, sleep latency, subjective sleepiness, and the PVT. These measures were repeated regularly 4 times each day (0900, 1300, 1700, and 2100) during the 58-hr rest and recovery period. Study consisted of focus groups, a driver survey and interviews with CMV drivers focused on the physical requirements (loading/unloading) across the industry. This was followed by a driving simulator study. 10 male truck drivers with long-haul truck driving backgrounds; aged 31 to 49, mean = 43.2 CMV drivers 1. Small number of subjects (n = 10). Subjects were studied in a simulator environment rather than a real-world setting. 2. As only a straight day schedule was examined, the conclusions drawn regarding the amount of cumulative fatigue and amount of recovery are restricted to this single schedule. Scope of Work: Sample Size: Industry Sector: Major Limitations:

3. Subjects were directed to take breaks of a specific length and told to get a good night’s sleep. As a result subjects may have not been as fatigued as drivers at the end of a week of driving in a real-world setting. This has implications for the conclusions that can be drawn regarding the amount of cumulative fatigue and amount of recovery time needed. 4. As subjects stayed at an apartment when not on duty during their driving week, the amount/quality of sleep they experienced may not be indicative of the sleep they would experience on the road. In addition, the amount of rest they had on the rest days may also be inflated, as social distractions in their home setting were not present. With respect to when there was evidence of fatigue in relation to cumulative time/days on task: 1. There was a gradual decline in driver response quality over time (hours at the wheel). There were slight performance degradations in the mid-afternoon, but there were improvements after each break, whether for rest, meals, or loading activities. The authors did not discuss how long the improvement effect lasted. 2. The rest breaks had an influence on critical safety measures. For example, the effects of 6.5 hr of driving were reduced to starting levels by the 1-hr lunch break for non- loading days. While the recovery effect of a rest break is not surprising, the magni- tude of the effect is striking. (Note: As the loading/unloading variable contributed to a significant interaction it is of use to examine the days when no such activity occurred, since these are more typical of the industry as a whole, and are free of the loading/ unloading variance). 3. After the morning physical activity, there was an improvement in driver response to crash-likely simulated situations, probably due to a short-term invigorating effect asso- ciated with physical exercise and a break in driving routine. 4. The afternoon loading/unloading session did not have the same effect on drivers. Driv- ing performance deteriorated more rapidly after the afternoon physical activity, sug- gesting that cumulative physical/general fatigue and time-of-day effects are sufficient to overpower some short-term effects of a change in activity. Driving performance did return to starting levels near the end of the day. 5. The ability to maintain speed within posted limits and gear shifting performance both deteriorated somewhat during the latter part of the driving day. The simultaneous occur- rence of the two suggests deterioration in physical coordination and vigilance late in the day, but there was no consistent linear relation to hours of driving. 6. The authors note that there is “no useful way to compare the cumulative effects of the 14/10 schedule with other possible schedules (including those logically subsumed, such as 10-hr and 12-hr duty periods) because the cumulative effects for each are con- founded.” However, what can be said about cumulative effects is that they “appear to be nil for practical measures (e.g., probe scores) and mild for parallel subjective measures such as subjective sleepiness.” Duty-day subjective sleepiness, reaction time response, and measures of driving performance showed a slight but statistically significant deteri- oration over the driving week, but driver response in crash-likely situations did not show cumulative deterioration. The schedule of 14 hr on duty/10 hr off duty (12 hr driving) for a 5-day week did not appear to produce significant cumulative fatigue over the 2-week testing period. 7. The mean sleep times recorded for the driving days were as follows: • Day 1 = 6.870; SD = 1.286; n = 10 • Day 2 = 6.454; SD = 0.685; n = 10 • Day 3 = 6.351; SD = 1.055; n = 10 • Day 4 = 6.215; SD = 0.921; n = 10 • Day 5 = 6.516; SD = 0.823; n = 10 Average: 6.4812 78 Findings

79 • Days 6 and 7: rest days • Day 8 = 6.201; SD = 1.104; n = 10 • Day 9 = 6.383; SD = 0.636; n = 10 • Day 10 = 6.447; SD = .619; n = 10 • Day 11 = 6.038; SD = 0.806; n = 10 • Day 12 = 6.026; SD = 0.954; n = 10 Average: 6.219 • Days 13 and 14: rest days • Day 15 = 5.666; SD = 1.228; n = 10 With respect to time to recovery (of performance, level of alertness) 1. The authors did not discuss differences in the rate of deterioration of driving perfor- mance between the first and second week. 2. The mean sleep times for the recovery days were as follows: • Day 6 = 6.364; SD = 1.315; n = 10 • Day 7 = 7.438; SD = 1.1251; n = 10 • Day 13 = 6.745; SD = 1.061; n = 10 • Day 14 = 7.778; SD = 1.708; n = 10 3. While there was an increase in measured sleep and a decrease in sleep latency on the first off-duty rest day following the end of the driving week, the authors do not believe that the peak sleep periods during the “weekend” days were due principally to sleep deprivation. They noted that drivers varied in the number of hours of sleep per night, and in a by-case examination of driver sleep patterns did not show a higher rebound for those who slept less during the driving week, indicating that the variation observed did not represent deprivation. They felt that the drivers did not appear to have accumulated sig- nificant sleep loss. 4. Sleep latency was measured between 2200 and 2230 on the last driving day (Friday) of each week. At this point, drivers were not ready to sleep, however tired they might have felt, since they had just been released from a 14-hr driving day. The second sleep latency measurement was taken between 0900 and 0930 the next morning (Saturday), shortly after the drivers had awakened from a night’s sleep. The third sleep latency measure- ment was taken at 1300 on Saturday and proved to be dramatically the shortest sleep latency. 5. Drivers returned to baseline reaction time performance and alertness within 24 hr after the end of a driving week, as shown by sleep latency, reaction time testing, and driver rating of subjective sleepiness. This effect was generally consistent across drivers. The typical recovery pattern involved extra sleep during the first rest day verified by wrist activity monitor, and an increased level of sleepiness during the afternoon of the first day (indicated by shorter sleep latency). With respect to individual differences 6. Age was correlated with lane performance (r = .508, p < .01) and shifting performance (r = −.287, p < .01). 7. Height/weight (a surrogate measure for general fitness) was correlated with lane perfor- mance (r = −.358, P < .001) and shifting performance (r = −.428, p < .001). (Word of caution: While strong correlations with age and height/weight appeared with largely physical tasks, they were absent or negligible in other variables such as mean probe score.)

Driver Fatigue/Alertness p. 37, FHWA-MC-99-140, “. . . there is “no useful way to compare the cumulative effects of the 14/10 schedule with other possible schedules (including those logically subsumed, such as 10-hour and 12-hour duty periods) because the cumulative effects for each are con- founded. The most that can be said about cumulative effects is that they “appear to be nil for practical measures (e.g., probe scores) and mild for parallel subjective measures such as subjective sleepiness.” p. 3, FHWA-MCRT-99-008, “Drivers returned to baseline reaction time performance and alertness within 24 hours after the end of a driving week, as shown by sleep latency, reac- tion time testing, and driver rating of subjective sleepiness. In daytime driving schedules like this one, resuming work after 24 hours of rest would cause severe circadian disruption. Drivers ought to resume duty only after a minimum of 36 hours rest.” Driver Duration p. 40, FHWA-MC-99-140, “. . . simple time on task is not a uniformly effective determiner of performance. Factors such as time-of-day (and its relation to circadian cycle) and rest break schedule are so influential that other factors customarily associated with perfor- mance deterioration over time are dwarfed. In this case, it is a reasonable observation that, in a typical day (morning to evening) shift, the difference between a 10- or 12-duty day and a 14-hour day is negligible. We caution, however, that this observation cuts both ways with respect to the suitability of a 14-hour duty schedule. We cannot say with certainty that this result would be observed with other than a day shift, since the powerful effects of circadian factors could interact with time on task and length of duty to produce very different results for different shift schedules.” p., 41, “FHWA-MC-99-140, “From the results of this study, we find no reason to believe that a schedule of 14 hours on duty, 12 hours driving, followed by 10 hours off duty, is likely to cause noticeable performance decrement on drivers, and it has the advantage of allow- ing five days of continuous work at such a schedule without the complication of offsetting the 24-hour circadian rhythm. That is, such a regularized 14/10 schedule permits drivers to maintain their work schedules in parallel to expected circadian body rhythm changes in physiology and performance. This conclusion is limited to conditions in which the driver is (1) conditioned or accustomed to the schedule being followed (that is, a change in shift that upsets the circadian rhythm would in all likelihood negate the 14/10 schedule much as it would a 16/8 or 12/12 or any other notional schedule); (2) the driver is allowed a reason- able break schedule; (3) the driving is accomplished on a typical day shift pattern (since night driving was not tested in this study); and (4) the off-duty time is actual off-duty time during which a driver may obtain sleep.” Driver Health No significant findings or assumptions concerning impact on health. 80 Findings Directly Related to HOS (include page references):

81 Dianne Davis Morrow, P.C. and Crum, M.R. (2004). “Antecedents of fatigue, close calls, and crashes among commercial motor-vehicle drivers.” Journal of Safety Research, 35 (1). This paper summarizes the results of a survey of CMV drivers in 116 trucking firms. The pur- pose of the study was to identify factors (i.e., fatigue inducing and company safety manage- ment factors) relevant to the prediction of driving while fatigued, close calls due to fatigue and actual crash involvement among CMV drivers engaged in intra- and interstate truck driv- ing work. “Findings indicated that fatigue-inducing factors inherent in driving work and safety practices accounted for appreciable variation in driving fatigued (R squared = 0.42) and close calls (R squared = 0.35), but not crash involvement. Driving while fatigued also accounted for incremental increases in the amount of variation in close calls, after consider- ation of inherent factors and safety practices.” The authors concluded “that safety practices (e.g., establishment of a strong safety culture, dispatcher scheduling practices, company assistance with fatiguing behaviors such as loading and unloading) have considerable poten- tial to offset fatigue-inducing factors associated with truck driving work.” This paper summarizes the results of a survey of CMV drivers in 116 trucking firms. Thirty- two of these firms were top safety-performing firms, 53 from average firms, and 31 from poor performing firms. Drivers were asked a number of questions about fatigue-inducing factors such workload, schedule regularity, difficulty finding rest places, adequacy of sleep, insufficient recovery, percent of time loading/unloading. In addition, participants were asked about the perceived safety climate in their company. The authors formulated 11 per- ceived safety climate items (e.g., “Our Company makes driving safety a top priority”) and asked drivers to record their level of agreement). Finally drivers were asked about their fatigue while driving (e.g., nodding off while driving, etc.,), as well as frequency of close calls and crashes. The authors proposed three models to account for the variation in fatigue while driving, close calls due to fatigue, and crash involvement. Proposition 1 specified that fatigue inducing factors would account for variation in these outcome measures. Proposi- tion 2 specified that “company safety management practices should account for variation in the outcome measures, controlling for fatigue-inducing factors associated with truck driv- ing work.” Proposition 3 contended that “fatigue while driving accounts for variation in the frequency of close calls due to fatigue and crash involvement, after controlling for fatigue-inducing factors and company safety management practices.” Survey conducted with CMV drivers. A literature review was conducted on fatigue-inducing factors, work overload, schedule regularity, disturbances in sleep patterns, insufficient recovery, and company safety management practices. Survey of CMV drivers in 116 trucking firms. At least one driver provided usable data from each firm. (4% female, 96% male; ages: 22 to 63; average age = 43; average number of driv- ing years: 14.92). CMV drivers The authors conclude their paper with a summary of the limitations of their research. They state that the primary limitations of this research are that it involves “potential sampling bias (e.g., low percentage of firms agreeing to participate in the project, safety director selection of drivers), the use of measures without established validity, and reliance on sin- gle item measures for the independent variables. In addition, they point out concerns with the reliance on driver self-report, and the possible limitation in the restriction in range asso- ciated with the self-report crash involvement measure. 1. “Fatigue-inducing factors inherent in driving work and safety practices” (e.g., schedule regularity, difficulty finding a place to rest, adequacy of sleep when working, insufficient Reviewer: Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings

recovery, percent of time loading/unloading, etc.) “accounted for appreciable variation in driving fatigue (R squared = 0.42) and close calls (R squared = 0.35), but not crash involvement.” Self-report measures were used to assess fatigue (i.e., 3-item measure). Crash involvement was measured using the sum of two items: (1) reportable accidents (to the company) and (2) chargeable accidents that drivers had been involved with over the last 2 years. Approximately one-fifth of the drivers reported having one or more reportable accidents, and approximately 4% reported having chargeable accidents. The raw data was adjusted to account for exposure and expressed on a per 100,000 mi basis. Drivers with reportable accidents had between 0.32 and 6.41 crashes per 100,000 mi, while those reporting chargeable accidents had between 0.29 and 1.03 crashes per 100,000 mi. The measure exhibited a Cronbach alpha of 0.85. 2. “Driving while fatigued accounted for incremental increases in the amount of variation in close calls, after consideration of inherent factors and safety practices.” 3. “. . . Safety practices (e.g., establishment of a strong safety culture, dispatcher schedul- ing practices, company assistance with fatiguing behaviors such as loading and unload- ing) have considerable potential to offset fatigue-inducing factors associated with truck driving work.” 4. While there is an assumption that employees will use off-duty time to engage in restora- tive activities, the insufficient recovery results reported in this study led the authors to con- clude that “drivers do not necessarily spend their non-work time in this manner.” While drivers may not engage in job-related activities during their recovery periods, some driv- ers do engage in activities and sleep patterns that lead them to report back to work already fatigued. The authors note that the results “suggest that the potential misuse of off-duty time can be mitigated by the presence of a strong safety climate or enactment of policies targeted at fatigue-inducing activities (i.e., companies can act to reduce this problem).” Driver Fatigue/Alertness p. 63, “Insufficient recovery was gauged by asking drivers how frequently they began a new “workweek” feeling tired or fatigued.” Just over half (53%) said this never or only rarely happened to them (scored “1”) while 47% indicated that this happened with greater fre- quency (scored “2”).” p. 65, “Fatigue-inducing factors, especially insufficient recovery, appear to play a role in determining whether a driver experiences fatigue and close calls due to fatigue.” p. 65, “The amount of time spent loading and unloading trucks appears to have a bearing on crash involvement, though the overall role of fatigue inducing factors was not predictive of crash involvement.”(i.e., more loading and unloading was associated with negative impacts). p. 65, “The joint ability of fatigue-inducing factors and safety practices accounted for 42% (p < .001; Model 1) of the variation in fatigue while driving.” p. 66, “Contrary to expectations, policies to minimize driving at night appeared to increase the frequency of close calls due to fatigue. However, it should be noted that policies to min- imize nighttime driving were negatively related (albeit non-significantly) to fatigue while driv- ing (beta = −.10, ns; Model 1), leaving the utility of this practice open to further debate.” p. 66, “Schedule regularity, difficulty in finding a place to rest, and insufficient recovery remained statistically significant contributors to the model.” p. 66, “Proposition 3 asserted that fatigue while driving accounts for variation in the fre- quency of close calls due to fatigue and crash involvement, after controlling for fatigue- inducing factors and company safety management practices . . . We conclude that Propo- sition 3 was supported in the case of close calls but not in the case of crash involvement.” 82 Findings Directly Related to HOS (include page references):

83 p. 66, “The models tested herein were able to account for modest amounts, around 40%, of the variation in fatigue and close calls dues to fatigue, but were unsuccessful in explaining crash involvement. While close calls (“near accidents”) are often used as proxies for crashes, these findings indicate that each outcome has unique antecedents and thus may require different explanations (e.g., percent of time spent loading was observed to be a good predictor of crashes but not related to fatigue or close calls.”). Driver Duration p. 63, “The number of 6-hour time blocks driven in the course of a day was measured by asking drivers to specify the time blocks they normally spent more than 10% of their driv- ing time: 6 a.m. to noon, noon to 6 p.m., 9 p.m. to midnight, and midnight to 6 a.m. . . . Just over half the drivers (50.9%) were able to limit their blocks to two, 27.6% reported three time blocks and 12.5% reported that they commonly worked during all four time blocks.” Driver Health No significant findings or assumptions concerning impact on health.

Dianne Davis Williamson, A., Feyer, A., and Friswell, R. (1996). “The impact of work practices on fatigue in long distance truck drivers.” Accident Analysis & Prevention, Vol. 28, No. 6, pp. 709–71. The aim of the study was to investigate the relationship between staged driving and fatigue. Professional truck drivers completed a 12-hr, 900 km trip under each of three driving regimes—a relay (staged) trip, a working hours regulated one-way (single) trip, and a one- way (flexible) trip with no working hours constraints. All of the observed trips took place overnight. The authors concluded “although there was some evidence that fatigue devel- oped differently within the three driving regimes (staged, single, and flexible), the levels of fatigue experienced by drivers increased markedly over all the trips. None of the regimes demonstrated any overall advantage in combating fatigue compared to the other regimes.” The authors conclude that it is clear from their findings that even relatively short 12-hr trips are tiring and that effective strategies for fatigue reduction need to be identified. In addi- tion, their finding that pre-trip level of fatigue appears to be an important determinant of later fatigue raises questions about the ongoing work schedules under which long distance drivers operate, “and highlights the need to allow adequate rest and recuperation between trips and between blocks of trips to prevent chronic sleep loss and to reduce fatigue.” Professional truck drivers completed a 12 hr, 900 km trip under each of three driving regimes—a relay (staged) trip, a working hours regulated one-way (single) trip, and a one- way (flexible) trip with no working hours constraints. “The staged trip entailed driving from Sydney or Melbourne to the trip midpoint (Tarcutta), exchanging trucks or loads with a driver coming in the opposite direction, and then returning to the point of origin.” The single one-way trips involved driving directly from Sydney to Melbourne, and the flexible one-way trips involved driving from Melbourne to Sydney.” “Under the regulations, drivers on single and staged trips were obliged to break for 30 min after each 5-hr period. Under the flexible regime drivers could choose to take breaks as often or as rarely as they needed with no con- straint on the time taken to complete the trip.” All of the observed trips took place overnight. Most trips began in the early evening and night between 1600 and 2359. The three driving regimes did not differ significantly in starting time. While, on average, the staged trips took longer to complete than the flexible trips, the trip lengths differed by only 40 min. The study employed subjective (e.g., Stanford Sleepiness Scale, etc.), physiological (e.g., heart rate), and performance (e.g., speed, steering variability, reaction time, etc.) “measures to examine the relationship between the characteristics of staged driving and the development of fatigue.” Field study with professional truck drivers who routinely ran staged operations between Sydney and Melbourne in Australia. Twenty-seven professional truck drivers (average age = 38.4; average years of commercial driving = 15.9 years Professional truck drivers The authors note that further investigation is needed to determine whether these findings would generalize to longer trips where there is greater potential for flexibility in break-taking to be effective. 1. “Although there was some evidence that fatigue developed differently within the three driving regimes (staged, single, and flexible), the levels of fatigue experienced by driv- ers increased markedly over all the trips.” 2. “None of the regimes demonstrated any overall advantage in combating fatigue com- pared to the other regimes.” 84 Reviewer: Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings

85 3. It is clear from the findings that “even relatively short 12-hour trips are tiring, and that effective strategies for fatigue reduction need to be identified.” 4. Pre-trip level of fatigue appears to be an important determinant of later fatigue. This raises questions about the ongoing work schedules under which long distance drivers operate, “and highlights the need to allow adequate rest and recuperation between trips and between blocks of trips to prevent chronic sleep loss and to reduce fatigue.” Driver Fatigue/Alertness p. 713, “Both the Stanford Sleepiness Scale ratings and the visual analogue scale ratings (Table 2) revealed a marked increase in fatigue between the beginnings and ends of the trips for all trip types.” p.. 713, “Drivers tended to feel most fatigued on staged trips and least fatigued on single trips, however, this pattern was in evidence before driving commenced and at posttrip had not been modified by the intervening driving regime.” p. 715, “. . . drivers’ performance on the vigilance, critical flicker fusion and unstable tracking tasks suggested heightened fatigue at the start of the staged trip, and for vigilance and unstable tracking, this impaired performance under the staged regime was maintained across the course of the trip. These findings are consistent with the higher fatigue ratings given by drivers before and after the staged trip.” p. 717, “Over all measures, the pattern of results suggests that fatigue increased across all trip types . . . There is clearly a need to identify those factors affecting the drivers’ pretrip fatigue and performance.” p. 718, “. . . the pretrip level of fatigue appeared to be an important determinant of later fatigue. This finding raises questions about the ongoing work schedules under which long distance drivers operate, and highlights the need to allow adequate rest and recuperation between trips and between blocks of trips to prevent chronic sleep loss and to reduce fatigue.” Driver Duration p. 712, “The number of breaks taken (Table 1) increased across flexible, single, and staged trips, suggesting an increasing need for rest as a function of driving regime. However, breaks were taken after similar periods of driving for the three trip types (Table 1). The longest driver period (4.5 hours) routinely occurred before the first break and the shortest drive period (2.5 to 3 hours) preceded the second break.” p. 712, “In summary, the pattern of break-taking suggests increased fatigue around the middle of the trips and greater overall fatigue on staged trips. However, these conclusions need to be treated cautiously because break-taking may have occurred for reasons other than providing a rest from driving, and at times of convenience, necessity or habit.” Driver Health No significant findings or assumptions concerning impact on health. Findings Directly Related to HOS (include page references):

Dianne Davis, Alison Smiley Williamson, A., Feyer, A.M., Friswell, R., and Finlay-Brown, S. (2000). “Demonstration proj- ect for fatigue management programs in the road transport industry: Summary of findings.” The aim of this project was to evaluate work-rest schedules to begin to identify some model work-rest schedules to provide companies and drivers flexibility in meeting their opera- tional needs and to manage fatigue most effectively. The paper is a summary of findings of the results of three different reports. Because this paper is a summary of findings, it does not include a great deal of detail. The first report describes the identification of three per- formance measures that have demonstrated sensitivity for detecting fatigue and its effects so that they can be used in developing models of work-rest schedules. The second and third reports focus on on-road and simulated evaluations of current and alternative work-rest schedules. The first step in this project involved a comparison of performance on a “range of perfor- mance tests under conditions in which study participants should be tired, with performance under conditions in which they had been exposed to varying doses of alcohol” to identify measures that have demonstrated sensitivity for detecting fatigue. Performance tests were administered at regular intervals over time with increasing sleep deprivation (i.e., partici- pants were kept awake a total of 28 hr) and increasing blood alcohol levels (BAC) (four doses of alcohol to achieve increasing BAC). The authors could then identify which tests were sensitive to increasing alcohol doses and which were sensitive to increasing sleep deprivation. The second and third reports focused on four evaluations, consisting of two evaluations of the current working hours regulations in New Zealand and two evaluations of alternative approaches to work-rest schedules. All the evaluations except one (a simulation) were con- ducted on-road using the performance measures developed in the first step of this project. Participants started the study after being on break for 24 hr to “obtain baseline information about performance when rested.” Ratings of fatigue and performance were then taken at “strategic points across the work-rest schedule between two long 24 hour breaks.” The alternative approaches to work-rest schedules were evaluated in a simulation study and an on-road study. The simulation study looked at the extension of the daily working hours limit from a “maximum of 14 hours in a 24-hour period to up to 16 hours in a 24-hour period. The overall schedule covered 60 hours. The longer hours were balanced by begin- ning and ending the schedule with a 6-hour break and having a mandatory 6-hour break at some point in the intervening 48 hours. Short breaks of at least 15 minutes were also required after every 3 hours of work. The evaluation was conducted as a simulation because it had not yet been authorized to be trialed on the road as part of the pilot FMP.” In con- trast, the second evaluation of an alternative approach to work-rest schedules could be con- ducted on the road because “it was in operation as part of the pilot FMP”. It “differed from the regulated hours regime by allowing for longer sustained periods of work at a stretch and splitting of the mandatory breaks between them. The regulated hours allow only 5 contin- uous hours of work before drivers take a break of at least 30 minutes. In this alternative schedule, drivers could work up to 6 continuous hours and only needed to take breaks in 15-minute periods, although they needed to take 30 minutes in total in every 6 hour period. The FMP also allowed drivers to divide the mandatory 6 hour continuous break into shorter sections. In all other ways, the work-rest schedule was the same as the regulated regime.” Identification of performance measures sensitive to fatigue and evaluations of current and alternative working hours regulations. Not stated 86 Reviewers: Title: Abstract: Methodology: Scope of Work: Sample Size:

87 Professional drivers The evaluation of regulated hours only reflects the effects of one cycle of the current regime on drivers who had low levels of fatigue to begin with. “Further research is needed to look at how the regulated regime manages fatigue over the longer term.” 1. While most of the tests showed deterioration in performance with increasing alcohol doses, not all the tests did so for increasing sleep deprivation. 2. The tests chosen to be most sensitive to fatigue were Simple Reaction Time, Mackworth Clock Vigilance test, and Dual Task. 3. “. . . 0.05% BAC equivalence occurred at between 17 and 19 hours of sleep deprivation for most tests. This means that after around 17 hours of wakefulness, performance capac- ity was sufficiently impaired to be of concern for safety.” 4. There was little evidence that current working hours led to performance decreases large enough to “constitute a significant safety risk compared to alcohol equivalent levels at 0.05% BAC.” 5. In the simulation study of an alternative compliance approach, drivers were able to man- age fatigue effectively over the first 16 hr of the schedule, however, their performance deteriorated significantly by the middle of the second 16-hr period. Performance at this time was “considerably poorer than the 0.05% BAC alcohol equivalence standard. It seems that the 6 hour break was insufficient to allow recovery and recuperation from the demands of the previous long day . . .” The work-rest schedule was “too demanding for drivers to manage fatigue effectively.” 6. The results of the road test evaluation of the second alternative compliance approach showed that “reaction speed showed a deterioration across the study to levels that were suggestive of an increased safety risk based on the 0.05% BAC equivalent standard for performance.” Driver Fatigue/Alertness p. 2, “Through a careful comparison of alcohol and sleep, performance capacity has deteriorated sufficiently to be of concern to the community due to an increased potential safety risk.” p. 3, “For the first evaluation of the regulated regime (CR 190, Evaluating a regulated hours regime on-road and an alternative compliance regime under simulated conditions) fatigue ratings were significantly higher when drivers returned to the depot at the end of the first trip and at the end of the study period compared to rested levels. Despite this, there were only a few significant changes in performance capacity.” p. 11, For evaluations of regulated regime: “Both evaluations showed, however, that per- formance capacity deteriorates and fatigue levels increase in relation to factors like increasing hours of work (especially night hours), short breaks and breaks that only allow short or poor quantity sleep (see Table 3). While fatigue and performance capacity seem to be maintained with safe limits under the regulated regime, these findings indicate that where drivers or companies take the work-rest schedules beyond the current limits, they are likely to be increasing the risk of performance decrements sufficient to compromise safety.” Driver Duration p. 20, “Evaluation of the current working hours regime suggests that provided drivers are rested to begin with, one full cycle of the regulated regime does not produce fatigue or per- formance capacity decrements that are of concern for safety. There is considerable evi- dence however that performance decrements increase significantly as the schedule becomes Industry Sector: Major Limitations: Findings Findings Directly Related to HOS (include page references):

more demanding. This is a warning signal for the development of alternative approaches to ensure that schedules are designed that do not simply increase the demands on drivers. The evidence from both evaluations of alternative compliance schedules suggested that they increased the demands on drivers, but did not balance them sufficiently with rest in order to allow recuperation and recovery from accumulated fatigue.” p. 20, “These results do not mean that the working hours regulatory regime is the only sat- isfactory approach to managing fatigue. The results show clearly that it is possible to increase trip length to 16 hours, say, and still maintain good performance levels. It is not possible, however, to continue to do 16 hour trips without a longer break than is usually allowed, even in the regulated regime.” p. 13, “Long work periods need to be balanced by longer rest periods. This study did not address the issue of the length of rest needed to recover sufficiently from a 16 hour work period. It only showed that a 6 hour break was not sufficient.” Driver Health No significant findings or assumptions concerning impact on health are stated in summary. 88

89 Dianne Davis, Alison Smiley Wylie, C.D. “Driver drowsiness, length of prior principal sleep periods, and naps.” (1998). Transportation Development Centre. Report No. TP 13237E. Wylie, C.D., Shultz, T., Miller, J.C., and Mitler, M.M. (1997). “Commercial motor vehicle driver rest periods and recovery of performance.” Wylie, C.D., Shultz, T., Miller, J.C., Mitler, M.M., and Mackie, R.R. (1996). “Commer- cial motor vehicle driver fatigue and alertness study.” (Executive Summary & Technical Summary). Mitler, M.M., Miller, J.C., Lipsitz, J.J., Walsh, J.K., and Wylie, C.D. (1997). “The sleep of long-haul truck drivers.” New England Journal of Medicine, 337(11). Freund, D. and Vespa, S. “U.S./Canada study of commercial motor vehicle driver fatigue and alertness.” Proceedings of the XIIIth World Meeting of the International Road Federa- tion, Toronto, Ontario. June 16–20, 1997. This paper summarizes the results of an on-road study with 80 drivers in the U.S. and Canada. The goal of this study was to assess fatigue related to Canadian versus U.S. driv- ing schedules. Data (e.g., loss of alertness, performance, etc.) were collected on drivers for a period of 16 weeks. Drivers drove one of four driving schedules. Time of day was the “strongest and most consistent factor influencing driver fatigue and alertness.” In contrast “hours of driving (time-on-task) was not as strong or consistent predictor of observed fatigue.” “There was some evidence of cumulative fatigue across days of driving.” The study used a between-subjects design involving four driving schedule conditions: C1: 10-hr daytime (5 consecutive days); C2: 10-hr rotating (5 consecutive days, starting 3 hr earlier each day); C3: 13-hr nighttime start (4 consecutive days); C4: 13-hr daytime start (4 consecutive days). The study design “was developed to comply with existing U.S. and Canadian hours-of-service regulations.” “The four schedules provided different amounts of time off between trips. Condition 1 provided about 11 hours off, while the other three con- ditions provided about 8 hours off.” Various measures were taken: driving task performance (e.g., lane tracking, steering wheel movement), driving speed and distance monitoring, per- formance on surrogate tests (i.e., code substitution, critical tracking test, simple response vig- ilance test), continuous video monitoring, physiological measures as well as driver-supplied information (e.g., daily logs, Stanford Sleepiness Scale rating). A follow-up study focused on five groups of CMV drivers. One group of five drivers worked nights (i.e., 4 × 13-hr nights, followed by 36 hours off, and then worked 4 × 13-hr nights) and the remaining four groups worked days. Three of the groups worked 4 × 13-hr days and had varying recovery time (i.e., group 1: 10 to 11 hr, three drivers; group 2: 36 hr, six drivers; group 3: 60 hr, six drivers) before working an additional day. The final group of five drivers worked 4 × 13-hr days, had 36 hr off and worked 4 additional days. Literature review. Field study involving Canadian and American CMV drivers. 80 male CMV drivers; 25 to 65 years old CMV drivers “The limitations of the study relate primarily to the lack of full control over the full range of conditions affecting alertness and fatigue and the inability to isolate some factors due Reviewers: Titles: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations:

to unavoidable confounding of variables, a consequence of the naturalistic approach to this study.” 1. Time of day was far more important than time on task or cumulative number of trips in predicting driver fatigue. 2. Drivers in the C3: Nighttime condition had the least amount of sleep of all the conditions. 3. “Night driving (e.g., from midnight to dawn) was associated with worse performance on four important criteria” (e.g., average lane tracking standard deviation, drowsiness, code substitution, and sleep length). 4. “There was some evidence of cumulative fatigue across days of driving. For example, performance on the Simple Response Vigilance Test declined during the last days of all four conditions.” 5. Drivers had approximately 2.5 hr less sleep than the amount of sleep they identified as their ideal. 6. Drowsiness in Conditions C3: Nighttime and C4: Daystart was markedly greater during night driving. Of episodes of drowsiness during on-road driving, 82% occurred between 1900 and 0659. 7. The follow-up study found that based on a small sample of drivers, 36 hr recovery was insufficient for day or night drivers, but especially for night drivers. Note: All following quotes are from Wylie 1996. Driver Fatigue/Alertness p. ES-8, “The strongest and most consistent factor influencing driver fatigue and alertness in this study was time of day.” p. ES-9, “Night driving (e.g., from midnight to dawn) was associated with worse perfor- mance on four important criteria . . .” (i.e. average lane tracking standard deviation, drowsiness, code substitution and sleep length). p. ES-9, “There was some evidence of cumulative fatigue across days of driving. For exam- ple, performance on the Simple Response Vigilance Test declined during the last days of all four conditions.” p. ES-10, “Overall, drivers obtained about 2 hours less time in bed and 2.5 hours less actual sleep than their reported “ideal” daily amount of sleep.” (i.e., ideal = 7.2 hr; actual sleep during study = 5.2 hr). p. 4-23, “The overall pattern was characterized by the longest sleep times in Condition C1-10day and the shortest in Condition C3-12nightstart . . .” (Total sleep time for: C1- 10day = 5.4 hr; C3-13nightstart = 3.9 hr) p. 4-33, “The observed prevalence of drowsiness formed a distinct peak about 8 hours wide, spanning late evening until dawn, and a 16-hour trough.” p. 4-32, “The prevalence of drowsiness in conditions C3-13nightstart and C4-13daystart was markedly greater during night driving.” p. 4-42, “There was probably greater drowsiness in Condition C2-10rotating, trips 4 and 5, because the rotating schedule had caused these last trips, on average, to be driven through the night. Although disruption of circadian rhythms and cumulative fatigue prob- ably contributed, time of day appeared to be a major factor.” 90 Findings Findings Directly Related to HOS (include page references):

91 Driver Duration p. ES-9, “Hours of driving (time-on-task) was not a strong or consistent predictor of observed fatigue.” Driver Health No significant findings or assumptions concerning impact on health.

92 SUMMARY OF FINDINGS OF LITERATURE The review of sources from the period 1996 onward sup- ports evidence in previous findings as follows: • Falling asleep at the wheel is a common experience for truck drivers. In a study of 567 drivers, almost one-fifth reported falling asleep at the wheel twice in the last 3 months (Hakkanen and Summala 2000). These are self-reports; the reality is likely to be more. • Night driving is associated with poor sleep. Of 4 schedules, drivers in the 13-hr night driving con- dition had the least sleep (3.9 hr total) (Wylie et al. 1998). • Night driving is associated with more falling asleep incidents. Of episodes of drowsiness during on-road driving, 82% occurred between 1900 and 0659 (Wylie et al. 1998). • Long-haul drivers get poor sleep. A comparison of long-haul and short-haul drivers found both obtained 7.5 hr sleep on average. However, long-haul drivers obtained 44% of their sleep during work-shift hours, suggesting that they spend a signifi- cant portion of the work shift in a state of partial sleep deprivation. (Balkin et al. 2000). • Night driving is associated with poorer driving performance. Lowered performance was found for drives of 1.5 hr in a simulator (Gilberg et al. 1996), and for nighttime on-road driving typical of trucking schedules (Wylie et al. 1998). • Reduced sleep at night is associated with poorer daytime performance and with inadequate recovery. A laboratory study of the effects of restricted night sleep on daytime simulator performance showed that reduced sleep is associated with poorer performance and that recovery to baseline requires more than 1 night of 8-hr sleep for those with 3, 5 or 7 hr in bed during the work week. For the 3-hr group, even 3 recovery nights of 8-hr sleep is not sufficient (Balkin et al. 2000). • Dangerous events are related to sleep deficit and pro- longed driving. In an on-road study, 20% of 1,249 drivers with less than 6 hr sleep had 40% of the critical incidents (Arnold et al. 1997). Frequent sleepiness-related prob- lems occurred in one-half of drivers who reported a com- bination of sleep deficit, prolonged driving, and lower self-perceived health (Hakkanen and Summala 2000). • Driving while fatigued increases likelihood of close calls. Driving while fatigued resulted in an increase in the variation in close calls, after inherent factors and safety practices were controlled for (Morrow and Crum 2004). Drivers involved in critical incidents were younger and less experienced and more likely to exhibit on the job drowsiness (Hanowski et al. 2000). • Time of day is far more important that hours of driving in predicting observed fatigue. Time of day was far more important than hours of driving (time on task) or cumulative number of trips in predicting fatigue (Wylie et al. 1998). Sources dating from 1996 onward contain new findings as follows: • Under ideal circumstances, long daytime hours with good sleep are not a problem. In a laboratory study, performance in the 7 and 9 hr time in bed groups was often indistinguishable and improved throughout the study. With 7 hr time in bed, impaired performance was only found on the more sen- sitive tasks. When sleep was restricted to 8 hr time in bed during recovery, performance of the group who had received 9 hr time in bed was slightly worse (Balkin et al. 2000). In a second laboratory study, the schedule of 14 hr on duty/10 hr off duty for a 5-day week did not appear to produce significant cumulative fatigue (O’Neill et al. 1999). However, subjects slept in an apartment and may not have been subject to normal home distractions, resulting in more sleep than usual. • Night sleep is important for recovery from a single day of driving and from several days of driving. A dramatic recovery with respect to fatigue was found in team drivers who stopped overnight in the middle of a 4- to 5-day trip (Feyer et al. 1997). A small study that examined 0-hr, 36-hr, and 60-hr recovery found that only partial recovery occurs after a 36-hr reset for both day and night drivers (Wylie et al. 1998). • Single drivers were more involved in incidents than team drivers. In an on-road study, single drivers were involved in four times more instances of very/extremely drowsy observer ratings than were team drivers and were more likely to push themselves when they were very tired (Dingus et al. 2001). • Insufficient recovery is related to close calls. Fatigue-inducing factors, especially insufficient recov- ery, are statistically associated with a driver experienc- ing fatigue and close calls due to fatigue (Morrow and Crum 2004). • Starting the work week feeling fatigued is a common experience for CMV drivers. Almost half of CMV drivers indicated that they started a new “work week” feeling tired more than “rarely” (Morrow and Crum 2004). In a study of team versus single drivers, team drivers started the week tired (Feyer et al. 1997). • Dangerous events related to drivers’ self-perceived health status. With respect to health, there were increased odds of drivers having more frequent difficulties in remaining

alert if the driver had poorer self-perceived health (Hakkanen and Summala 2000). • Poorer lane tracking and gear shifting related to poorer general fitness. Height/weight (a surrogate measure for general fit- ness) was correlated with lane performance and shifting performance. These correlations were absent for more cognitive, less physical tasks (O’Neill et al. 1999). RESEARCH LIMITATIONS The most notable lack of research concerns recovery requirements, particularly for night drivers. Long-distance truck drivers frequently drive at night to avoid traffic and, because they work at night, must sleep during the day. Because of circadian rhythms, we do not perform well at night, par- ticularly during the early morning hours, and sleep obtained during the day is shorter and of poorer quality than sleep obtained at night. Currently, HOS regulations treat daytime and nighttime driving equally both in terms of hours permit- ted and required recovery time. The new regulations will allow for longer hours in a 7-day period provided the driver takes a 34-hr reset period. Research concerning the accept- ability of this reset period is very limited (a laboratory study of daytime performance finding good recovery after 1 night of sleep if previous night’s sleep had been 7 or 9 hr, a study of team drivers in a remote area of Australia finding dramatic recovery after a single overnight stop in the middle of a 4- to 5-day trip, a small on-road study showing that neither day nor night drivers, and especially not night drivers recovered fully following a 36-hr reset). COMPLETE PRIMARY SOURCES AND ABSTRACTS Arnold, P.K., Hartley, L.R., Hochstadt, D., and Penna, F. “Hours of work, and perceptions of fatigue among truck drivers.” (1997). Accident Analysis & Prevention, 29 (4) 471–77. Drivers and companies operating in the heavy road trans- port industry were surveyed about drivers’ hours of work and perception of the causes and magnitude of fatigue as an indus- try problem. These drivers were operating in a state which, at the time of the survey, did not restrict driving hours for heavy haulage drivers. On the day of the interview, estimates based on retrospective and prospective reports, suggest that in a 24-hr period about 38% of drivers exceed 14 hr of driving, and 51% exceed 14 hr of driving plus other non-driving work. About 12% of drivers reported less than 4 hr of sleep on 1 or more working days in the week preceding the interview. These drivers are likely to be operating their vehicles while having a significant sleep debt. About 20% of drivers reported less than 6 hr sleep before starting their current journey, but nearly 40% of dangerous events that occurred on the journey were reported by these drivers (p < 0.05). Many drivers and company representatives reported fatigue to be a problem for other drivers, but considered themselves or their companies’ drivers to be relatively unaffected by fatigue. There were dif- ferences between drivers’ and companies’ perceptions about causes of fatigue, and strategies that should be used to man- age it. The results obtained from these drivers in an unregu- lated state were compared with earlier findings from drivers in states where driving hours restrictions are in place. Balkin, T., Thome, D., Sing, H., Thomas, M., Redmond, D., Wesensten, N., Williams, J., Hall, S., and Belenky, G. (2000). “Effects of sleep schedules on commercial motor vehicle driver performance.” Department of Transporta- tion, Federal Motor Carrier Safety Administration. The Balkin et al. (2000) study involved an actigraphic assessment of the sleep of 50 long- and short-haul CMV driv- ers ages 21 to 65 for 20 consecutive days. The drivers wore the Walter Reed wrist actigraphs at all times except when bathing or showering. In addition, they completed sleep logs on driver’s daily log sheets to gather subjective information about sleep times; sleep latency; arousals during sleep; alert- ness upon awakening; naps (number and duration); and self- reported caffeine, alcohol, and drug use. The data from each actigraph were downloaded to a personal computer, and each 24-hr actigraph recording period was examined for sleep in its entirety regardless of the duty status type or length indi- cated on the daily log sheet. Baas, P.H. (Transport Engineering Research New Zealand (TERNZ)), Charlton, S., and Bastin, G. (2000) “Survey of New Zealand truck driver fatigue and fitness for duty.” 4th International Conference on Fatigue and Transpor- tation, Fremantle, Western Australia. This paper presents recent research on compliance with current driving hours regulations, the effectiveness of using driving hours to predict fatigue, and alternative compliance and enforcement options. The paper describes results of a major survey of truck driver fatigue in New Zealand, a review of international compliance and enforcement procedures, and research focusing on the social forces and influences that affect truck drivers. The survey of truck drivers was based on interviews and performance tests collected from 600 truck driv- ers at depots, wharves, markets, and other locations through- out the North Island of New Zealand. The initial results from the first 100 drivers found a sizable number of drivers exceed- ing the allowable driving hours, high levels of fatigue and sleepiness, and interesting differences between line-haul and local delivery drivers. A related research project into the social processes/relationships that affect truck drivers has resulted in a good understanding of the social conditions that influence cultural change and the actions of truck drivers and fleet managers. In this paper we will have particular regard to these processes in the construction of ideas concerning safety. This includes an understanding of the role of major 93

stakeholders, such as freight forwarders and the enforcement agencies with respect to drivers and their conditions, actions and understanding of the road transport industry. This knowl- edge coupled with the survey results and an understanding of compliance and enforcement alternatives will be used to explore potential fatigue management options. (a) For the cov- ering entry of this conference, see ITRD abstract no. E204477. AN: E204480 Charlton, S.G., and Baas, P.H. “Fatigue and fitness for duty of New Zealand truck drivers.” (1998). Road Safety Research, Policing, Education Conference. Wellington, New Zealand. Vol. 2. pp. 214–9. The effects of driver fatigue have been implicated in a large number of truck crashes and road fatalities in other countries. While there are no extensive studies of fatigue-related road accidents in New Zealand, the road characteristics and driving environment make any decrease in performance due to driver fatigue a significant potential threat to road safety. This paper describes an on-going Road Safety Trust-sponsored study of how common driver fatigue is in New Zealand and the degree to which these truck drivers suffer from fatigue related effects. Using a portable driving simulator installed in a car- avan, volunteer truck drivers are asked to complete a brief survey (about their driving hours and their amount of sleep in the past 48 hr, how sleepiness affects them, and the level of fatigue they feel at that moment), and go for a “drive” on the driving simulator (measuring their vehicle control and reac- tion times) as they stop their trucks at depots, rest stops, and cargo terminals throughout the day and night. In comparison with indirect measures of fatigue, such as inspection of driv- ing hours in log books, the fitness-for-duty test has obvious job relevance (measuring actual driving performance) and enjoys a high degree of driver acceptance. FMCSA Tech Brief, 2001 (FMCSA-MCRT-01-006). “Impact of local/short-haul operations on driver fatigue: Field study.” FMCSA Tech Brief, 2000/09 (FMCSA-MCRT-00-015). “Effects of sleep schedules on commercial motor vehicle driver performance—Part 2.” Federal Motor Carrier Safety Administration. “Impact of sleeper berth usage on driver fatigue.” (2002). Report Number: FMCSA-RT-02-050. The goal of this project was to assess the impact that sleeper- berth use has on operator alertness. The participants in this study were 47 males and 9 females, constituting 13 teams and 30 single drivers. All drivers who participated in the study were recruited from one of four for-hire commercial trucking com- panies. Two tractors, a 1997 Volvo L4 VN-series tractor and a 1995 Peterbilt 379, with functionally identical instrumentation packages and data collection systems, were used. The data acquisition system functioned to record four camera views, 94 including the driver’s face; driving performance information, including steering, lane departure, and braking; sleeper-berth environmental data, including noise, vibration, and tempera- ture; subjective alertness ratings; and data from the Nightcap sleep monitoring system. The results obtained are provided in the document. Feyer, A.M., Williamson, A., and Friswell, R. “Balancing work and rest to combat driver fatigue: An investigation of two-up driving in Australia.” (1997). Accident Analysis & Prevention, 29 (4) pp. 541–53. This study is the fourth in a series examining driver fatigue in the Australian long-distance road transport industry. Thirty-seven long-haul truck drivers were measured on a rou- tine 4,500-km round trip. Two types of driving operations were compared, single driving, involving a solo driver, and two-up driving, where a pair of drivers operate a truck con- tinuously and alternate between work and rest. Two-up driv- ers reported higher levels of fatigue than single drivers overall and tended to show poorer levels of performance. However, this result appeared to reflect differential fatigue at the start of the trip. Both two-up and single drivers showed marked increase in fatigue across the first half of the trip, fol- lowed by a substantial recovery of alertness and performance provided that drivers had stationary overnight rest at mid trip or had shorter trips. Fatigue continued to increase on the sec- ond half of the trip for drivers who did longer trips without the benefit of a substantial night rest or who did not have access to on-board rest, that is, single drivers. The use of overnight rest, in combination with two-up driving, appeared to be the most successful strategy for managing fatigue across the trip. Freund, D. and Vespa, S. (1997) “U.S./Canada study of commercial motor vehicle driver fatigue and alertness.” Proceedings of the XIIIth World Meeting of the Inter- national Road Federation, Toronto, Ontario. June 16–20, 1997. The CMV Driver Fatigue and Alertness Study was the largest and most comprehensive over-the-road study of its kind ever conducted in North America. Its primary purposes were to establish measurable relationships between CMV driver activities and physiological and psychological indicators of fatigue and reduced alertness and to provide a scientifically valid basis to determine the potential for revisiting the 60-year- old HOS regulations. Work-related factors thought to influence the development of fatigue, loss of alertness, and degraded per- formance in CMV drivers were studied within an operational setting of real-life, revenue-generating trips. These included the amount of time spent driving during a work period; the number of consecutive days of driving; the time of day when driving took place; and schedule regularity. It was found that the strongest and most consistent factor influencing driver fatigue and alertness was time of day; drowsiness, as observed in video recordings of the driver’s face, was markedly greater

during night driving than during daytime driving. The number of hours of driving (time on task) was not a strong or consis- tent predictor of observed fatigue. Other study findings noted that the number of driving periods was not a strong or consis- tent fatigue predictor; that there was a low correlation between drivers’ subjective self-ratings of alertness/sleepiness and concurrent objective performance measures; and that there was a large difference between the mount of sleep drivers reported as their “ideal” and the amount they obtained during principal sleep periods in the study setting. While there is no single solution to the fatigue problem, much can be done to address driver fatigue through a combination of innovative HOS regulation and enforcement, education, driver work scheduling, innovative fatigue management programs, driver screening, fitness for duty and alertness monitoring systems, and additional research. For the covering abstract of this con- ference, see IRRD number 872978. Gillberg, M., Kecklund, G., and Akerstedt, T. (1996). “Sleepiness and performance of professional drivers in a truck simulator—comparisons between day and night driving.” Journal of Sleep Research, 5, pp. 12–15. Previous research has shown that night driving perfor- mance may be seriously affected by sleepiness. The present study compared daytime and nighttime performance of pro- fessional drivers on a simulated truck driving task. A sec- ondary purpose was whether a nap or a rest pause would affect performance. Nine professional drivers participated in a coun- terbalanced design. The conditions were day driving (DAY- DRIVE), night driving (NIGHTDRIVE), night driving with a 30-min rest (NIGHTREST), and night driving with a 30-min nap (NIGHTNAP). Each condition consisted of three consec- utive 30-min periods. For the DAYDRIVE and NIGHT- DRIVE, all periods were spent driving while the second period was either a rest pause or a nap for the other two con- ditions. Mean speed, standard deviation of speed, and stan- dard deviation for lane position were recorded. Self ratings of sleepiness were obtained before and after each 30-min period. Reaction time tests and 10-min standardized EEG/EOG recordings were obtained before and after each condition. EEG/EOG recordings were obtained before and after each condition. EEGs/EOGs were also recorded continuously dur- ing driving. The effects on driving were small but significant: night driving was slower, with a higher variability of speed, and had higher variability of lane position. Subjective and EEG/EOG sleepiness were clearly higher during the night conditions. Reaction time performance was not significantly affected by conditions. Neither the nap nor the rest pause had any effect. Hakkanen, H. and Summala, H. (2000). “Driver sleepiness- related problems, health status, and prolonged driving among professional heavy-vehicle drivers.” Transporta- tion Human Factors, 2(2), 151–171. Questionnaire data concerning the frequency of prolonged driving, sleepiness-related problems while driving, and per- 95 sonal health status were analyzed from 567 professional driv- ers with 5 work descriptions. Of the drivers, 31% had been regularly driving more than 10 hr, 19% reported having dozed off at least twice while driving, and 8% reported a near- miss situation due to dozing off during the past 3 months. Sleepiness-related problems while driving appeared across all driver groups, including drivers transporting dangerous goods and bus drivers, and were strongly related to pro- longed driving, sleep deficit and drivers’ health status. The effects of the latter factors were interactive and cumulative: Frequent sleepiness-related problems occurred in more than one-half of the drivers with the combination of prolonged driv- ing, sleep deficit, and lowered self-perceived health. The results give unreserved support for regulating driving hours and increase concern of the connection between professional drivers’ health status and sleepiness-related problems while driving. Hanowski, R. J., Wierwille, W. W., Gellatly, A. W., Early, N., and Dingus, T. A. (2000). “Impact of local short-haul operations on driver fatigue.” Department of Trans- portation Federal Motor Carrier Safety Administration. The goal of the Hanowski et al. (2000) study, which examined the impact of the individual differences of truck drivers on the occurrence of driving incidents, was to study fatigue experienced by short-haul truck drivers. Forty-two male short-haul drivers (mean age = 31) participated in the study. Drivers completed 2 weeks of Monday–Friday day- time driving on normal delivery routes that were within 100 mi of home. Their distribution of work consisted of driving (28%), loading/unloading (35%), other assignments (26%), waiting to unload (7%), eating (2%), resting (0.5%) and other activities (1.5%). A number of measures were used to assess the fatigue, inattention, and drowsiness of the drivers, including analysis of a videotape of the 3-min interval preceding the start of a critical incident. An incident was defined as a control move- ment exceeding a threshold based on driver or analyst input. Analysts recorded eye transitions and the proportion of time that the driver’s eyes were closed/nearly closed, or off the road, during these 3-min intervals. The drivers’ mean sleep was 6.43 hr per night (sleep log) and 5.31 hr based on the actiwatch. Drivers who showed evi- dence of fatigue and were involved in fatigue-related inci- dents had less sleep and of a poorer quality than drivers who did not show signs of fatigue. Twenty-one percent of the inci- dents implicated fatigue as a contributor based on observer assessments of drowsiness and the increase in proportion of time with eyes closed or nearly closed. Over the 2-week period, there were 77 incidents (average 1.8 per driver) where the driver was judged to be at fault. With respect to individual differences, 10 of the 42 drivers were involved in 86% of the incidents. The younger and less expe- rienced drivers were significantly more likely to be involved in critical incidents and exhibited higher on the job drowsiness.

The strength of this study is that it focuses on individual differences and it has strong face validity with respect to traf- fic safety issues. The main weakness from the perspective of our study is that it does not address recovery directly. Klauer, S.G., Dingus, T.A., Neale, V.L. and Carroll, R.J. (2003). “The effects of fatigue on driver performance for single and team long-haul truck drivers.” Driving Assess- ment 2003—The Second International Driving Sympo- sium on Human Factors in Driver Assessment, Training and Vehicle Design. Park City, Utah. Driver fatigue is an important safety issue for long-haul truck drivers. To provide an efficient means of obtaining sleep, long-haul truck drivers often use tractors equipped with sleeper-berth units. Depending on the type of cargo and distances traveled, long-haul truck drivers either drive in teams or alone as single drivers. Team drivers, therefore, typ- ically sleep in a moving truck whereas single drivers sleep in a stationary truck. It has been hypothesized that sleeping in a moving truck could adversely affect the sleep quality and, therefore, the alertness level of team drivers. A naturalistic data collection system was developed and installed in two Class 8 heavy trucks. This trigger-based system consisted of vehicle sensors and cameras that allowed the experimenters to obtain the driving performance and driver alertness data for analysis of fatigue. Fatigue was measured using both objective and subjective measures that were recorded before and after sleep and while driving. Fatigue and driving per- formance were compared for single versus team drivers to determine which driver type acquired the greatest sleep deficit during a trip. Results suggest that single drivers were more frequently involved in critical incidents while exhibiting extreme drowsiness than were team drivers by a factor of 4 to 1. These results are discussed in relation to the general safety of single versus team truck operations. Mitler, M.M., Miller, J.C., Lipsitz, J.J., Walsh, J.K., and Wylie, C.D. (1997). “The sleep of long-haul truck driv- ers.” New England Journal of Medicine, 337(11). Morrow, P.C. and Crum, M.R. (2004) “Antecedents of fatigue, close calls, and crashes among commercial motor-vehicle drivers.” Journal of Safety Research, 35 (1). Minimizing driver fatigue among CMV drivers is a major safety issue in the United States. This paper examines the effects of potentially fatigue-inducing factors inherent in truck driving work and company safety management in explaining (1) drivers driving while fatigued, (2) the frequency of close calls due to fatigue, and (3) actual crashes among CMV driv- ers. Data for this study is derived from a survey of CMV driv- ers in 116 trucking firms, with all data being driver-reported. The relative roles of fatigue-inducing factors and safety man- agement practices in explaining variation in fatigue, close calls, and crashes are reported, along with the roles of fatigue 96 in affecting close calls and crashes via hierarchical regres- sion. Findings indicate that fatigue-inducing factors inherent in driving work and safety practices accounted for apprecia- ble variation in driving fatigue (R sq. = 0.42) and close calls (R sq. = 0.35), but not crash involvement. Driving while fatigued also accounted for incremental increases in the amount of variation in close calls, after considering inherent factors/safety practices. O’Neill, T.R., Krueger, G.P., Van Hemel, S.B., and McGowan, A.L. (1999). “Effects of operating practices on commercial driver alertness.” Rep. No. FHWA-MC-99- 140, Office of Motor Carrier and Highway Safety, Fed- eral Highway Administration, Washington, D.C. This driving simulator study sought to assess truck driver fatigue or alertness as affected by non-driving, but on-duty activities, such as loading/unloading a vehicle. It also exam- ined the effects of driver performance on extended HOS— 14 hr on duty/10 hr off duty (12 hr daytime driving, 0700 to 2100). Researchers examined driver performance over a 15-day period. In addition, the amount of nonduty time (rest and recovery) needed to reestablish baseline fitness for duty was investigated. O’Neill, T.R., Krueger, G.P., Van Hemel, S.B., McGowan, A.L. and Rogers, W.C. (1999) “Effects of cargo loading and unloading on truck driver alertness.” Transportation Research Record 1686, pp. 42–48. The relationship between physical and mental fatigue is not well understood or well documented, a lapse that affects under- standing of the interaction between loading and unloading activities and safe operation in the trucking industry. This experiment addresses the effects of loading and unloading on driving performance by measuring driving impairment in vol- unteer truck drivers operating a truck-driving simulator. Ten drivers participated, each for 17 days, including 2 driving weeks of 5 days with 14-hr duty cycles separated by two 58-hr rest periods. During one of the driving weeks, partic- ipants were given a significant hand-loading task, 3 hr of hand-loading pallets of boxes on 3 of 5 days; during the remaining week, only driving tasks were scheduled. Perfor- mance measurement focused on driver responses to planned and unplanned crash-likely challenges and vigilance tasks, supported by simulator-mediated driving indicators, such as lane-keeping performance. Measures of subjective drowsi- ness also were maintained. The effects of the loading and unloading task were mixed. There was an initial improve- ment in alertness, apparently because of the break in activity and a period of exercise; however, this effect wore off as the day progressed and may have contributed to a decrease in overall performance after 12 to 14 hr of duty. O’Neill, T. R., Krueger, G. P., Van Hemel, S. B., and McGowan, A. L. (1999). “Effects of operating practices on commercial driver alertness.” Rep. No. FHWA-MC-

99-140, Office of Motor Carrier and Highway Safety, Federal Highway Administration, Washington, D.C. The goal of the O’Neill et al. (1999) study was to assess the effects of operating practices, namely schedule, loading and recovery, on alertness. Ten male CMV drivers participated in 1 week of driving operations in a simulator followed by 58 hr of recovery time. This was followed by another week of driv- ing, 58 hr of recovery time and a final driving day to verify performance after recovery. Half of the drivers performed 3 days of loading in the first week (i.e., 2 × 1.5-hr sessions) and had no loading in the second week. The remaining driv- ers did the reverse (i.e., loaded in week 2). On loading days, drivers performed two 90-min loading/unloading sessions during the driving day, one in the morning, and one in the afternoon. The drivers worked 14 hr on duty (i.e., 12 hr driv- ing plus scheduled breaks) beginning at 0700, followed by 10 hr off duty. Measures of sleepiness, sleep length, psychomotor perfor- mance, and driving simulator performance were collected. The sleep measures included the Stanford sleepiness scale, self- alertness scales and wrist actigraphs (i.e., sleep length). Mea- sures were collected using the PVT, which has been shown in previous studies to be very sensitive to sleepiness. The PVT is a 10-min period of reaction time performance where drivers respond as fast as possible to brief visual stimuli. Reaction time and lapses (reaction times exceeding 500 m/sec) are recorded. Driving simulator performance measures included lane posi- tion, speed maintenance, and shifting performance. Response probes (e.g., tire blowout, merge squeeze, fog, etc.) were used and driver response was evaluated by expert trainers on a three-point scale. Probes provided tests of driver vigilance, alertness, and response time. Individual differences in performance in relation to age and height/weight were assessed. The age of the drivers was correlated with lane (r = 0.508, p < 0.01) and shifting perfor- mance (r = −0.287, p < 0.01). Drivers height/weight ratio (a surrogate measure for general fitness) was correlated with poorer lane performance (r = −0.358, p < 0.001) and shifting performance (r = −0.428, p < 0.001). Overall, there was a gradual decline in driver response quality, as measured by response probes, with hours of driv- ing. There were improvements after each break, regardless of whether it was a rest, meal, or loading activity. After 6.5 hr of driving, drivers were returned to starting levels of safety (as measured by response to probes) by a 45-min lunch break. The ability to maintain speed within posted limits and gear shifting performance deteriorated somewhat during the latter part of the driving day but there was no consistent linear rela- tion to hours of driving. There was an improvement in driver response to crash- likely simulated situations after the morning physical activ- ity. However, gear shifting increased, indicating inefficiency in attention and co-ordination, and there was greater lane posi- tion variability after the morning loading session. The only effect of the afternoon loading session appeared to be an 97 increase in cognitive errors, that is, lapses in vigilance lead- ing to missed turns. Over the driving week, there was a slight but statistically significant deterioration in subjective sleepiness, reaction time response, and measures of driving performance over each working day. However, driver response in crash-likely situa- tions did not show cumulative deterioration. The schedule of 14 hr on duty/10 hr off duty (12 hr driving) for a 5-day week did not appear to produce significant cumulative fatigue over the 2-week testing period. The drivers returned to baseline levels of reaction time, driv- ing simulator performance, and alertness within 24 hr of recovery time after the end of a driving week as shown by sleep latency, reaction time testing, and driver rating of sub- jective sleepiness. However, it should be noted that drivers lived in an apartment during testing; therefore, sleep may not have been typical of normal conditions during recovery, where drivers must deal with family and social obligations which may result in reduced sleep. Rogers, W. (2000). “Effects of operating practices on commercial driver alertness.” Proceeding of the Confer- ence Traffic Safety on Two Continents held in Malmo, Sweden, September 20–22, 1999. The aim of the study presented was to assess the effects of lorry driver loading or unloading on subsequent driver alert- ness and to measure and document lorry drivers’ performance on a 14 hr on (with 12 hr driving)/10 hr off daytime schedule coupled with a weekend recovery process over a 58-hr off- duty period between two successive weeks of simulated driv- ing. Measurements of probe performance, cognitive errors, lane performance and gear performance were carried out. Sleep patterns, sleep latency and subjective sleepiness were also measured in order to assess the effect of the rest and recovery required to re-establish alertness and fitness for duty. For the covering abstract of the conference, see ITRD E204692. Tech Brief (1999) (FHWA-MCRT-99-008) “Effects of operating practices on commercial driver alertness.” Williamson, A., Feyer, A.M., Friswell, R., and Finlay- Brown, S. (2000). “Demonstration project for fatigue management programs in the road transport industry: Summary of findings.” This document is the final summary of a series of three reports of a project on the development of model work-rest schedules that have demonstrated effectiveness for managing driver fatigue in the long distance road transport industry. The purpose of these studies was to help the industry in designing work-rest schedules to provide additional flexibil- ity for companies and drivers to meet their operational needs but also manage fatigue most effectively. The report provides an overview of the findings of each of the three studies. The first study developed a set of fatigue-sensitive performance

measures and alcohol-equivalent standards for each of them. The results also demonstrated sleep deprivation of 17 hr or more produced decrements in performance capacity equivalent to the community-accepted standard of 0.05% BAC. They also showed that long distance drivers appeared to cope with the demands of sleep deprivation better than non-professional driv- ers. The second and third reports detailed the evaluation of four work-rest schedules, two of which complied with the current working hours regulations and two were alternative schedules that did not comply with the regulations. The eval- uations were carried out on the road while drivers were doing their normal trips. The exception was one of the alternative compliance schedule evaluations which were done with pro- fessional long distance drivers in a simulation mode rather than on-road. The results of the regulated hours evaluations showed that as long as drivers were rested before their trips, the regulated regime produced increased fatigue and pro- duced some performance decrements at the end of a work period between long 24-hr breaks. The level of effect was not significantly high however, relative to alcohol-equivalent standards. In contrast, the alternative compliance schedule evaluations demonstrated that it is possible to introduce flex- ibility in scheduling such as by extending the length of work periods, but only if an adequate balance is maintained between work and rest. Williamson, A., Feyer, A., and Friswell, R. (1996). “The impact of work practices on fatigue in long distance truck drivers.” Accident Analysis & Prevention, Vol. 28, No. 6, 709–719. Both long- and short-haul drivers averaged approximately 7.5 hr of sleep per night, which is within normal limits for adults. However, in contrast to short-haul drivers who only obtained 3% of their sleep during on-duty periods, long-haul drivers obtained 44% of their sleep during on-duty periods. Short-haul drivers were more likely to consolidate their daily sleep into a single sleep period. As long-haul drivers obtained almost half of their daily sleep during work-shift hours (mainly sleep-berth time), it appears that they spend a significant por- tion of the work shift in a state of partial sleep deprivation, until the opportunity to obtain recovery sleep on duty pre- sents itself. There was no off-duty duration that guaranteed adequate sleep for the long- or short-haul drivers. As drivers likely use a substantial portion of their off-duty time to attend to per- sonal business, off-duty time must be of sufficient duration to allow drivers to accomplish these tasks and to obtain suffi- cient sleep. This may be particularly important for long-haul drivers, who often did not sleep at all during off-duty periods. The bulk of the first (main) daily sleep bouts for short-haul drivers were initiated between 2000 and 0200. Sleep bouts initiated at these times lasted longer (i.e., clustered between 6 and 10 hr) than sleep bouts initiated at other times of day. Several of the sleep bouts initiated between these times lasted longer than 12 hr. 98 Similar to the short-haul drivers, the majority of long-haul drivers’ first sleep bouts were initiated between 2200 and 0359. However, long-haul drivers initiated their first sleep bouts more frequently during 0000 and 0359. The duration of long-haul drivers’ first sleep bouts clustered between 6 and 10 hr in duration. Sleep bouts exceeding 10 hr in duration were uncommon and none exceeded 12 hr. Some sleep bouts were initiated in the early and late afternoon hours (1200 to 1959) and, unlike short-haul drivers, almost half of the first sleep bouts initiated during this time frame were longer than 4 hr in duration. There were large day-to-day variations in total sleep time for drivers in both groups. Sleep times varied for some long- and short-haul drivers by up to 11.2 hr across the 20 study days for the long- and short-haul drivers. Other drivers main- tained more consistent sleep/wake schedules. Some drivers showed a pattern that suggested chronic sleep restriction with intermittent bouts of extended recovery sleep. The authors believed that this suggested that although work-rest sched- ules can be devised to help minimize CMV driver sleep debt, optimal enhancement of driver alertness and performance will require additional and imaginative approaches. The strength of this study is that all periods of sleep, not just those taken off duty, were recorded for a large group of CMV drivers over an extended period of time. The main lim- itation as far as this study is concerned is that the issue of recovery was not addressed specifically. Wylie, C.D. “Driver drowsiness, length of prior principal sleep periods, and naps.” (1998). Transportation Devel- opment Centre. Report No. TP 13237E. The purpose of this study was to assess the relationships between prevalence of driver drowsiness observed on a trip, length of prior principal sleep periods, and naps taken during the trip, based on the data collected from actual revenue runs of the Driver Fatigue and Alertness Study (DFAS) and the Commercial Motor Vehicle Driver Rest Periods and Recov- ery of Performance Study. A rhythmic time of day variation was the strongest influence found on drowsiness, followed by length of the last main sleep. A mathematical model was developed that describes these effects. It was found that half the naps studied were taken in apparent absence of drowsi- ness, and half appeared to be taken in response to sudden increases in drowsiness. Naps in trips with judged drowsiness appeared to result in a recovery effect, compared with the rel- atively high levels of drowsiness seen in the hour prior to napping. However, drowsiness remained substantially ele- vated for 2 hr after napping. Wylie, C.D., Shultz, T., Miller, J.C., and Mitler, M.M. (1997). “Commercial motor vehicle driver rest periods and recovery of performance.” The purpose of this study was to assess the “recovery” effect of 0, 1, and 2 workdays off on driver fatigue and alert- ness. It was hypothesized that there would be some level of

improvement in dependent measures of driver performance on trips following the time off. The study involved 25 of the 40 drivers who participated in the two Canadian observa- tional conditions of the joint study by Canada and the United States known as DFAS. Field data were collected from 55 trips, in addition to those of the DFAS, and resulted in five new observational conditions that spanned a maximum of 8 workdays, nominally with 12 hr, 36 hr, and 48 hr of time off after the fourth workday. Three conditions included the 36-hr off-duty period, of which two had drivers do 4 more workdays following time off while the third had drivers do 1 more workday. Two conditions included 12 hr and 48 hr of time off and these had 1 more workday follow the time off. The data collection equipment and procedures were similar to those of the DFAS study and were described in detail in the final report issued on that project. Measures, which were identical to those used in the DFAS, included EEG, face video recordings, vehicle lane tracking, and computerized surrogate performance tests. Because of the smaller number of drivers who participated in this “recovery” study by compari- son with the DFAS, the statistical tests did not have the same power to detect effects. For 1 workday off (i.e., 36 hr), there was (1) no objective evidence of driver recovery; (2) some improvement in driver subjective feeling reflected by self- rating, although this could be a reflection of driver expecta- tion of recovery; (3) for day-start drivers, some increase in the amount of sleep obtained during time off; and (4) for night-start drivers, interference with work-rest patterns and less sleep during time off. For 2 workdays off (i.e., 48 hr) there was no objective evidence of driver recovery although the statistical power of the tests to detect recovery effects was not high because of random variation associated with the smaller number of drivers. Wylie, C.D., Shultz, T., Miller, J.C., Mitler, M.M., and Mackie, R.R. “Commercial motor vehicle driver fatigue and alertness study.” This is the full final report on the largest and most com- prehensive over-the-road study of CMV driver fatigue ever conducted in North America. The data collection involved 80 drivers in the United States and Canada who were moni- tored over a period of 16 weeks. A number of work-related factors thought to influence the development of fatigue, loss of alertness, and degraded performance in CMV drivers was studied within an operational setting of real-life, revenue- generating trips. These included the amount of time spent driv- ing during a work period, the number of consecutive days of driving, the time of day when driving took place, and sched- ule regularity. In Chapter 1, the reader is provided with the background to the study as well as the study’s overall objec- tives and the approach used in their attainment. Chapter 2 presents a detailed literature review on driver fatigue and its measurement, as well as the involvement of fatigue in crashes that was conducted in preparation for the study and consid- ered in the formulation of the study’s own conclusions and 99 recommendations. Chapter 3 presents the study methodology and data collections methods. Chapter 4 presents the detailed results. Chapter 5 provides an overview of the results and the study’s conclusions and recommendations. For the amount of sleep and the 4 to 5 days of driving observed for each driver in this study, it was found that the strongest and most consis- tent factor influencing driver fatigue and alertness was time of day; drowsiness, as observed in video recordings of the driver’s face, was markedly greater during night driving than during daytime driving. The number of hours of driving (time on task) and cumulative number of days were not strong or consistent predictors of observed fatigue. Numerous other findings are provided relating to scientific methodologies and fatigue countermeasure concepts. SECONDARY SOURCES Abrams, C., Schultz, T., and Wylie, C.D. (1997). “Commer- cial motor vehicle driver fatigue, alertness, and countermea- sures survey.” U.S. Department of Transportation, Federal Highway Administration. No. FHWA-MC-99-067. Akerstedt et al. (2000). “Sleepiness and days of recovery.” Anund, A., Kecklund, G., and Larsson, J. (2002). “Fatigued drivers in focus.” Swedish National Road Administration. Apparies et al. (1998). “A psychophysiological investigation of the effects of driving longer-combination vehicles.” American Trucking Associations, Inc. SB: TRB-TRIS. TI: Eye-Activity Measures of Fatigue and Napping as a Fatigue Countermeasure. SO: 1999/01. 9709-9802 pp.164 (Figs., Tabs., Refs., 11 App.) PY: 1999. RN: Report Number: FHWA-MC-99-028; Report Number: Final Report; Contract/Grant Number: DTFH61-96-00022. AB: This study investigated (1) the potential use of an eye tracking system for detecting reduced driver alertness and (2) the impact of prophylactic napping on driver performance and alertness. The study used traditional behavioral and phys- iological measures of alertness. In addition, an unobtrusive eye tracker attached to the simulator structure was used to measure eye and eyelid behavior. The results showed clear time-of-day and time on task effects for the following eye closure measures: partial closures during fixations, speed of slow eyelid closure (SEC), blink duration, and blink frequency. Eye closures during fixations exhibited the following alert- ness monitoring characteristics: (1) the cyclic phases of a driver experiencing brief lapses of alertness and recovery, (2) a continuous decline ultimately leading to an off-road simula- tor crash, (3) an early warning potential of 10 min or more, (4) a dramatic decline in the measure beginning 2 to 3 min

before an off-road simulator crash. SEC events and blink duration showed sustained increases with time on task and time of day. A preliminary algorithm for detecting level of alertness was developed. This algorithm uses the eye closure measure in a way that includes partial eye closures during fix- ations, blink frequency, blink duration, and speed of eye clo- sure effects. The 3-hr afternoon nap increased the subjects’ nighttime alertness and improved driving performance. Ben- eficial effects of the afternoon nap on nighttime driving per- formance included significantly fewer crashes, shorter run completion times, and smaller standard deviations of lane position. The results provide evidence that the 3-hr afternoon nap was effective in reducing sleepiness levels during the following night and suggest that prophylactic naps may be more beneficial than recuperative naps during all-night driv- ing situations. AN: 00763223 Balkin et al. (2000). “Effects of sleep schedules on commer- cial motor vehicle driver performance.” Brice, C. and Smith, A. SB: IRRD-OECD. TI: Caffeine and fatigue: mental performance and driving. SO: International Conference on Fatigue and Transportation, 4th, 2000, Fremantle, Western Australia. 2000. 32 p. (12 Refs.) PY: 2000. AB: The majority of studies to date have investigated the behavioural effects of caffeine in laboratory experiments using artificial tasks. It is now important to ask whether sim- ilar effects are observed in simulations of real-life activities, such as driving, and to consider whether consumption of caf- feine can reduce fatigue over long time periods, for instance over the working day. A number of studies show that caffeine can improve driving performance of fatigued drivers. In the current study 3mg/kg caffeine was found to improve steering accuracy in drivers carrying out a 1-hr simulated drive. In addition, measures of mood and performance of artificial tasks were recorded in this study and these also showed the benefits of consuming caffeine. These findings suggest that changes in the laboratory may reflect a general benefit of caffeine that is also observed in real-1ife situations. Further evidence from Smith examining the effects of caffeine on performance effi- ciency over the working day has shown the benefits of caf- feine consumption on measures of sustained attention and alertness. Furthermore, this study also provided evidence to suggest that caffeine is often consumed when alertness is low to maximize alertness and performance efficiency. The impli- cations of these findings in terms of road safety are also con- sidered. (a) For the covering entry of this conference, see ITRD abstract no. E204477. AN: E204481 Brill, J.C., Hancock, P.A., and Gilson, R.D. SB: TRB-TRIS. 100 TI: Driver Fatigue: Is Something Missing? CA: University of Iowa, Iowa City, IA. SO: Conference Title: Driving Assessment 2003: The Second International Driving Symposium on Human Factors in Driver Assessment, Training and Vehicle Design. Location: Park City, Utah. Sponsored by: FHWA; FMCSA; Honda R&D Americas, Inc.; Motorola; NHTSA; Univ. of Iowa; Nissan Technical Center North America; Univ. of Minnesota; Vir- ginia Tech; Seeing Machines—Australia; UMTRI; TTI; Univ. of Leeds, UK; Human Factors and Ergonomics Society; and TRB. Held: 20030721-20030724. 2003. pp. 138–142 (Refs.) PY: 2003. AB: Drowsiness and fatigue are serious problems in all trans- portation systems. One persistent issue is the lack of an agreed definition of these respective energetic states. This paper reviews the theoretical approaches (cognitive versus physiological) framing the driver fatigue problem. Known contributing factors to drowsiness include sleep debt, circa- dian rhythm, and shift work. However, it is also suggested that certain inherent physiological reactions engaged in responses to motion itself represent a previously unrecog- nized but significant source of fatigue. The impact of this fac- tor is confirmed through comparisons of studies that either have or have not included prolonged motion. AN: 00970486 Brown, W.J. SB: IRRD-OECD. TI: Interaction Between Extended Duty Hours and Circadian Rhythms: Consequent Effects on Long-Haul Driver Alert- ness and Performance. SO: Proceedings of the 29th Annual Meeting of the Canadian Transportation Research Forum: Going the Distance, Victo- ria, British Columbia, May 15–18, 1994. pp. 532–547. PY: 1994. AB: A major Canadian rail disaster in 1986 resulted in the loss of 26 lives and $30 million in property damage. The investigation demonstrated that severe disruptions to the engineer’s circadian rhythms caused by erratic schedules and extended duty hours impaired engineer performance result- ing in the rail disaster. This finding is supported by GAO studies (1992, 1993) on rail safety which showed similar results. The purpose of the present study is to determine whether the work-rest patterns of long-haul truck drivers are similar to those of train engineers and the consequences for safety in the trucking industry. For the covering abstract of this conference, see IRRD number 863285. Brown, J., Horberry, T., and Anderson, J. SB: IRRD-OECD. TI: Investigation of the effects of driver distraction. SO: Road Safety Research, Policing and Education Confer- ence, 2003, Sydney, New South Wales, Australia. 2003. 97-105 (Vol. 2) (38 Refs.) PY: 2003.

RN: 0 73105 395 8. AB: The MUARC advanced car driving simulator was used to undertake a study that examined the effects of distraction upon driving performance for drivers in three age groups. There were two in-car distractions: operating the car audio system and conducting a simulated hands-free mobile phone conversation. The study employed a hazard perception task, whereby the effects of distraction were assessed in terms of drivers’ reactions to pedestrians and other hazards in the roadway. Older drivers (over 60 years old) drove more slowly when they were distracted by the audio system and in the complex driving environment. Younger people (18 to 25 years old) maintained a more constant speed compared with mid- dle aged (30 to 45 years old) and older drivers (over 60). Fatigue caused by loss of sleep the night before the test or by the driving task itself did not affect driver performance. The authors concluded that the in-vehicle tasks of interact- ing with the audio system and conducting a simulated hands- free mobile phone conversation do impair several aspects of driving performance. (a) For the covering entry of this con- ference, see ITRD abstract no. E210298. AN: E210429 Charlton, S.G. and Isler, R.B. SB: IRRD-OECD. TI: Road Safety Research at Waikato University in New Zealand. SO: International Conference on Traffic and Transport Psy- chology—ICTTP 2000, Held 4–7 September 2000, Berne, Switzerland—Keynotes, Symposia, Thematic Sessions, Workshops, Posters, List of Participants and Word Viewer— CD ROM. 2001. (12 Refs.) PY: 2001. AB: The University of Waikato’s Traffic and Road Safety Research Group (TARS) was founded in 1993. Since then, the capabilities and research output of TARS have grown steadily, developing good relationships with industry, gov- ernmental, and regulatory end users in the transport and road safety communities. Currently, in a government-funded proj- ect, TARS researchers are employing advanced driving sim- ulator techniques and instrumented vehicles in order to develop human factors models characterizing driving performance and decisionmaking in various driving situations. Fatigue and Fitness for Duty in New Zealand Truck Drivers is another current project funded by Road Safety Trust. Using a portable driving simulator installed in a caravan, volunteer truck driv- ers are asked to complete a brief survey and take a diagnos- tic driving fatigue test at rest stops, depots, and cargo terminals throughout the day and night. Another TARS project involves teaching novice drivers appropriate eye scanning while nego- tiating curves. By using sophisticated eye tracking equip- ment, TARS researchers can detect and correct inappropriate looking behaviours in a safe environment of a driving simu- lator and in real traffic situations. For the covering abstract, see ITRD E113725. AN: E114139 101 DeValck, E. and Cluydts, R. SB: TRB-TRIS. TI: Slow-Release Caffeine as a Countermeasure to Driver Sleepiness Induced by Partial Sleep Deprivation. SO: Journal of Sleep Research. 2001. 10(3) pp. 203–209 (Refs.) PY: 2001. AB: This paper studied the effect of partial sleep deprivation (PSD) on driving abilities, as measured with a driving simula- tor, and the value of slow-release caffeine as a countermeasure to the expected performance decrements. Twelve subjects (20 to 25 years old) underwent four experimental conditions: 4.5 or 7.5 hr time in bed, both with 300 mg slow-release caf- feine or placebo. Driving performance was measured twice by a 45-min driving task on a simulator. Subjective sleepiness/ alertness and mood were assessed 4 times by the Stanford Sleepiness Scale and the Profile of Mood States. After 4.5 hr, as compared with 7.5 hr time in bed, drifting and speed devi- ation were higher, but only the effect on the first variable reached significance. In the placebo condition at 13 hr, acci- dent liability increased after PSD. Subjective sleepiness was higher in the 4.5 hr time in bed group. Findings suggest that a lack of sleep can lead to a significant driving performance impairment, and that slow-release caffeine can serve as a valuable countermeasure to the performance decrements. AN: 00932761 Desmond, P.A., Hancock, P.A., and Monette, J.L. SB: TRB-TRIS. TI: Fatigue and Automation-Induced Impairments in Simu- lated Driving Performance. SO: Transportation Research Record. 1998. (1628) pp. 8–14 (4 Fig., 24 Ref.) PY: 1998. RN: 0309064732. AB: A driving simulator study investigated the effect of automation of the driving task on performance under fatigu- ing driving conditions. In the study, drivers performed both a manual drive, in which they had full control over the driving task, and an automated drive, in which the vehicle was con- trolled by an automated driving system. During both drives, three perturbing events occurred at early, intermediate, and late phases in the drives: in the automated drive, a failure in automation caused the vehicle to drift toward the edge of the road; in the manual drive, wind gusts resulted in the vehicle drifting in the same direction and magnitude as the “drifts” in the automated drive. Following automation failure, drivers were forced to control the vehicle manually until the system became operational again. Drivers’ lateral control of the vehi- cle was assessed during three phases of manual control in both drives. The results indicate that performance recovery was better when drivers had full manual control of the vehi- cle throughout the drive, rather than when drivers were forced to drive manually following automation failure. Drivers also experienced increased tiredness, and physical and perceptual fatigue symptoms following both drives. The findings have

important implications for the design of intelligent trans- portation systems. Systems that reduce the driver’s percep- tions of task demands of driving are likely to undermobilize effort in fatigued drivers. Thus, the results strongly support the contention that human-centered transportation strategies, in which the driver is involved in the driving task, are supe- rior to total automation. AN: 00755015 Desmond, P. “Efficiency of vehicle-based data to predict lane departure arising from loss of alertness due to fatigue.” (1996). Proceedings of the 40th Annual Conference of the Associa- tion for the Advancement of Automotive Medicine. October 7–9, 363–76. Fairclough, S.H. and Graham, R. SB: TRB-TRIS. TI: Impairment of Driving Performance Caused by Sleep Deprivation or Alcohol: A Comparative Study. SO: Human Factors. 1999/03. 41(1) pp. 118–128 (2 Fig., 2 Tab., 27 Ref.) PY: 1999. RN: Contract/Grant Number: TR 1047. AB: This study assessed the relative impact of partial sleep deprivation (restriction to 4 hr of sleep before testing) and full sleep deprivation (no sleep on the night before testing) on 2 hr of simulated driving, compared with an alcohol treat- ment (mean BAC = 0.07%). Data were collected from 64 male participants on the primary driving task, psychophysi- ology (0.1 Hz heart rate variability), and subjective self- assessment. Results revealed that the full sleep deprivation group and alcohol group exhibited a safety-critical decline in lane-keeping performance. The partial sleep deprivation group exhibited only noncritical alterations in primary task performance. Both sleep-deprived groups were characterized by subjective discomfort and an awareness of reduced per- formance capability. These subjective symptoms were not perceived by the alcohol group. The findings are discussed with reference to the development of systems for the online diagnosis of driver fatigue. Potential applications of this research include the formulation of performance criteria to be encompassed within a driver impairment monitoring system. AN: 00765019 Fairclough, S.H. and van Winsum, W. SB: TRB-TRIS. TI: The Influence of Impairment Feedback on Driver Behav- ior: A Simulator Study. SO: Transportation Human Factors. 2000. 2(3) pp. 229–246 (4 Fig., 4 Tab., 32 Ref..) PY: 2000. AB: A variety of impairment-detection technologies have been developed as potential countermeasures to the degrada- tion of driving performance due to the influence of fatigue, alcohol, drugs, emotional stress, and distraction. The major- 102 ity of the research has focused on the development of tech- nology, that is, the construction of sensitive and reliable sen- sor apparatus or associated algorithms, or both. Few studies have been concerned with those driver-system interactions issues underlying this category of technology. Eighteen male participants took part in a repeated measure design in which they performed simulated journeys with and without impair- ment feedback. The diagnosis and assessment of impairment were based on the quality of vehicular control. Impairment feedback was presented in the form of two interface designs, one providing three levels of feedback and another capable of nine levels of feedback. The results indicated that impair- ment feedback counteracts the characteristic degradation of driving performance due to time on task with respect to vehic- ular control. However, the presence of feedback (in either form) failed to influence participants’ decision to discontinue the journey. In addition, impairment feedback failed to sig- nificantly influence psychophysiological effort, subjective fatigue, or subjective mental workload. The authors also dis- cuss the implications of these finding for future research and development. AN: 00812272 Fatigue Expert Group. SB: IRRD-OECD. TI: Fatigue Expert Group: options for regulatory approach to fatigue in drivers of heavy vehicles in Australia and New Zealand. SO: Report. 2001/02. (CR 202) 70 p. PY: 2001. RN: 0-642-54478-6. AB: This report was commissioned jointly by the National Road Transport Commission of Australia, the Australian Transport Safety Bureau, and the New Zealand Land Trans- port Safety Authority. The fatigue expert group comprised leading Australian and New Zealand experts in sleep, shift work, and road safety who collaborated with the participat- ing agencies and industry representatives to construct a set of evidence-based design principles for future fatigue regula- tory options. The group considered that the management of driver fatigue is not a matter for operators and drivers alone, and emphasised the requirements and practices of others in the transport supply chain. The chain of responsibility provi- sions in road transport legislation are designed to highlight that on-road performance is closely related to the decisions made by customers, consignors and loaders. The expert group was conscious of the need to provide a flexible and practica- ble framework in which fatigue could be actively managed by all those who are part of the supply chain. The group agreed on the following principles for designing better regu- lations: provision for minimum sleep periods, the opportunity for sleep and time of day influences; taking account of the cumulative nature of fatigue and sleep loss; taking account of the effect of night work on driving performance and both qual- ity and quantify of sleep; taking account of duration of work- ing time; and provision of short breaks within working time.

The group considered that any policy approach to the man- agement of fatigue in drivers of heavy vehicles must address these factors and proposed a possible model for the applica- tion of these design principles. AN: E204309 Filiatrault, D.D., Vavrik, J., Kuzeljevic, B., and Cooper, P.J. SB: TRB-TRIS. TI: The Effect of Rest-Schedule Orientation on Sleep Qual- ity of Commercial Drivers. SO: Conference Title: 43rd Annual Proceedings of the Asso- ciation for the Advancement of Automotive Medicine. Loca- tion: Barcelona (Sitges), Spain. Sponsored by: Association for the Advancement of Automotive Medicine. Held: 19990920– 19990921. Association for the Advancement of Auto Medi- cine Proc. 1999. pp. 329–343 (1 Fig., 7 Tab., Refs.) PY: 1999. AB: A study was conducted to examine the relationship between sleep quality and how CMV drivers balanced conflict when the need to rest interfered with their ability to maintain tight delivery schedules. Face-to-face interviews were con- ducted with 188 CMV drivers to collect physiological data and self-reported measures. Multivariate linear regression models were developed to analyze relationships between sleep quality, sleep quantity, symptoms of obstructive sleep apnea, and how schedule-based priorities were established. A significant correlation was found between sleep quality and how preference was given by CMV drivers, when symptoms of fatigue were detected, to balance conflict between the need to rest and the real or perceived duty to comply with externally- imposed schedule demands. AN: 00784208 Frith, W.J. SB: IRRD-OECD. TI: A Case Control Study of Heavy Vehicle Drivers’ Work- ing Time and Safety. SO: 17TH ARRB Conference, Gold Coast, Queensland, 15–19 August 1994; Proceedings; Volume 17, Part 5. 1994. pp. 17–30 (13 Refs.) PY: 1994. AB: In New Zealand, heavy vehicle drivers carry log books in which details of their driving hours must be recorded. It was decided to use this information to carry out a study on the risk of crash with respect to driving hours and other time intervals related to the drivers’ working lives. In the study, a case group of heavy vehicles involved in crashes (for which details of drivers’ hours were known from their log books) was compared with a control group of vehicles. The control group was selected by police going to the scenes of crashes on an anniversary of the crash, at the same time of day as the crash, and stopping a heavy vehicle. Where possible a vehi- cle was selected which was travelling in the same direction as the crash vehicle and which was of a similar configuration. Evidence was found of an increased crash risk in those cases 103 where driving exceeded 8 hr since the driver’s last compul- sory 10-hr off-duty period (as recorded in the log book). There were no other significant differences between the two groups with respect to other time intervals related to driving habits. There was a significant difference between the age distribution of the crash and control drivers with the crash driv- ers generally being younger. (a) For the covering abstract of this conference, see IRRD abstract no. 861222. AN: 861294 Gale, A.G.(Ed.), Desmond, P.A., and Matthews, G. SB: IRRD-OECD. TI: The effects of motivational and perceptual-based inter- ventions on fatigue-related decrements in simulated driving performance. SO: Vision in Vehicles—VII. 1999. pp. 149–56 (8 Refs.) PY: 1999. RN: 0-08-043671-4. AB: The aim of this study is to explore the differing predic- tions which may be derived from motivational and feedback hypotheses concerning fatigue-related decrements. The study explores these hypotheses by examining the effects of three types of interventions on drivers’ lateral control: motiva- tional, when subjects were presented with instruction that driv- ing skill was being measured; enhanced feedback, when the simulated road surface changed colour if the car deviated from a central lane; and reduced feedback, when the simu- lated environment was presented as being the same colour as the road surface. Driving performance was measured under conditions of task-induced fatigue and on a control drive. The findings of the study showed that the control drive produced greater subjective fatigue than the fatigue drive itself, princi- pally categorised as heightened boredom or apathy. The find- ings have implications for in-vehicle countermeasures to fatigue. (a) For the covering abstract, see ITRD E106152. AN: E106168 Gale, A.G.(Ed.), Desmond, P.A. and Matthews, G. SB: IRRD-OECD. TI: Task-induced fatigue effects on simulated driving performance. SO: Vision in Vehicles—VI. 1998. pp. 115–22 (12 Refs.) PY: 1998. RN: 0-08-43579-3. AB: Resource theories and dynamic models of stress and sus- tained performance make conflicting predictions concerning the nature of the interaction between fatigue effects and task demands. Resource theories suggest that fatigue may deplete attentional resources, so that detrimental effects of fatigue on performance are exacerbated when the task is highly demand- ing. Matthews et al. (1996) suggest that a variety of stress states may disrupt matching of effort to task demands. If so, the fatigued driver may fail to mobilize effort effectively when the task appears undemanding. These two conflicting hypotheses were tested with the Aston Driver Simulator, a

microcomputer-controlled fixed-base simulator of moderate fidelity (see Matthews et al., 1996). In the present study, driv- ers performed both a fatiguing drive, in the first part of which a fatigue-induction procedure was added to the pri- mary task of driving and a control drive with no additional fatigue-induction procedure. The effects of the fatigue manip- ulation on drivers’ subjective states were assessed by a selec- tion of subjective measures. For the covering abstract, see IRRD E102207. AN: E102219 Prepared by Margaret Gordetsky. SB: TRB-TRIS. TI: Australian Studies Urge Flexible Driving Hours, Fixed Rest Periods. SO: Transport Topics. 2001/03/19. PY: 2001. AB: Subtitle: Several Agencies Work on Fatigue-Fighting Policies. AN: 00907369. Gouin, V., Sagot, J.C. and Roussel, B. SB: TRB-TRIS. TI: Train Drivers’ Fatigue During a Seven Hour Daytime Trip. In: Engineering Psychology and Cognitive Ergonom- ics. Aerospace and Transportation Systems. CA: Ashgate Publishing Company, 131 Main Street, Bur- lington, VT. SO: Conference Title: Third International Conference on Engineering Psychology and Cognitive Ergonomics. Aero- space and Transportation Systems. Location: Edinburgh, Scotland. Sponsored by: College of Aeronautics, Cranfield University. Held: 20001025–20001027. 2001. pp. 455–462 (4 Fig., Refs.) PY: 2001. RN: 0754613372. AB: A continuous daytime driving period of 7 hr is common on French railways. A question often arises of the fatigue felt by drivers during such long driving times. Described in this paper is the methodology and given is a part of the results obtained during the Paris-Nice line, 6 hr 40 min of driving. The results focus on the psychological and behavioral aspects of the high speed, long driving task. No feeling of fatigue is shown as expressed by the drivers in subjective evaluation. Yet, the behavioral adjustments observed clearly indicate that the task took its toll. The train drivers’ experience makes these adjustments possible. AN: 00934408 Grunstein, R.R., Desai, A., Marks, G., Barlett, D., and Jankelson, D. ”The interaction of mild obstructive sleep apnea, sleep deprivation, and circadian factors in driving risk.” (2003). Road Safety Research, Policing and Education Conference, pp. 309–14 (Vol. 2) (5 Refs.) 104 Grunstein, R.R., Desai, A., Marks, G., Williams, A. and Barlett, D. (Woolcock Institute of Medical Research), and Jankelson, D. (St. Vincent’s Clinic. Sleep Disorders Service) SB: IRRD-OECD. TI: The interaction of mild obstructive sleep apnea, sleep deprivation, and circadian factors in driving risk. SO: Road Safety Research, Policing and Education Confer- ence, 2003, Sydney, New South Wales, Australia. 2003. pp. 309–14 (Vol. 2) (5 Refs.) PY: 2003. RN: 0 73105 395 8. AB: Obstructive sleep apnea (OSA) is a breathing disorder occurring in sleep, with important nighttime and daytime consequences. This study primarily sought to examine the added effect of fatigue promoting factors (sleep deprivation and time of day) on driving performance and cognitive func- tion in mild OSA patients. Currently licensed male drivers (25 to 55 years old) underwent overnight polysomnography to identify the presence of mild OSA. Clear effects of sleep deprivation and time of day were found in all subjects but no significant group differences were found. Although mild OSA drivers were not different to the control group in their response to sleep deprivation or time of day influences, they were less aware of their impairment due to sleep deprivation. In one reaction time task, mild OSA drivers showed greater impairment than controls at certain times of the day after sleep deprivation. (a) For the covering entry of this conference, see ITRD abstract no. E210298. AN: E210461 Haile, J. SB: IRRD-OECD. TI: A visit to Canadian Pacific Railways, 25–27 Septem- ber 1995. SO: Fatigue and Accidents: A Multi-Modal Approach. Pro- ceedings of a Conference Organised by the Parliamentary Advisory Council for Transport Safety, Held March 1996, London, UK. 1996/03. pp. 99–102. PY: 1996. AB: The CANALERT project, a study of Canadian freight train drivers and their working hours, is described. Forty vol- unteer drivers were known to be on duty for up to 18 hr (usu- ally 12 to 16 hr) with up to a 4-hr rest period mid shift. A 1 day on, 1 day off shift pattern was worked. There was also a maximum driving mileage per month. The study was under- taken with the removal of the previous blame culture sur- rounding individuals who had fallen asleep. These drivers were monitored using sleep tracking diaries, 24-hr activity monitoring, questionnaires, and human physiology monitor- ing. New measures tested included rostering to the individ- ual’s body clock by restricting return journey start times, training staff and families in the importance of the body clock, improvement of the bunk house facilities, allowing short 30-min naps during excessively long shifts, and allowing driv- ers to listen to music through headphones. The drivers said

they felt fitter after the implementation of the new measures. The relevance of the study to UK rail services is discussed. For the covering abstract, see ITRD E111306. AN: E111310 Hancock, P.A. (Ed.), Desmond, P.A. (Ed.), Brookhuis, K.A., and DeWaard, D. SB: IRRD-OECD. TI: Assessment of drivers’ workload: performance and sub- jective and physiological indexes. SO: Stress, Workload and Fatigue. 2001. pp. 321–33. PY: 2001. RN: 0-8058-3178-9. AB: There are many reasons that the measurement of driv- ers’ mental workload has great interest these days and will increasingly enjoy this status in the near future. Accidents are numerous, seemingly ineradicable, very costly, and largely attributable to the human factor. Human errors in the sense of imperfect perception, insufficient attention, and inade- quate information processing are the major causes of the bulk of the accidents on the road (Smiley and Brookhuis 1987, Treat et al. 1977). Although both low and high mental work- loads are undoubtedly basic conditions for these errors, an exact relation between mental workload and accident causa- tion is not easily established or easily measured in practice. The measurement of drivers’ mental workload offers oppor- tunities and pitfalls, as illustrated in De Waard’s model of driver performance, demands, and mental workload (De Waard 1996). Although stability of primary measures of driving per- formance over time is what the drivers’ goals are, the condi- tions are variable and sometimes strongly demanding and require effort in variable “amounts” that at times are beyond capacity. The accident proneness that follows such condi- tions is the (for the time being irrefutable) rationale for the measurement of drivers’ mental workload. For the covering abstract, see ITRD E108674. AN: E108678 Hartley, L.R. (Ed.) and Richardson, J.H. SB: IRRD-OECD. TI: The Development of a Driver Alertness Monitoring System. SO: Fatigue and Driving. Driver Impairment, Driver Fatigue and Driving Simulation. 1995. pp. 219–29 (7 Refs.) PY: 1995. RN: 0-7484-0262-4. AB: This chapter describes the monitoring of driver alertness as part of a project to develop a reliable in-vehicle warning system which could be incorporated into an intelligent vehi- cle highway system. Driver fatigue was measured in a series of trials. The first used a laboratory simulator to collect psy- chophysiological data from drivers experiencing levels of fatigue that could not be induced on public roads. The second trial involved a real driving task on a private airfield with sleep-deprived drivers. The final trial used a 150-mi motor- 105 way loop without sleep deprivation. Graphs are presented which show changes in drowsiness with time. For the cover- ing abstract, see IRRD 876074. AN: 876092 Hartley, L.R. SB: TRB-TRIS. TI: Beyond One Size Fits All Hours of Service Regulations. CA: American Trucking Associations, Inc, Alexandria, VA. SO: Conference Title: Managing Fatigue in Transportation. Location: Tampa, Florida. Sponsored by: American Trucking Associations, Association of American Railroads, Federal Highway Administration, Federal Railroad Administration, National Highway Traffic Safety Administration, and National Transportation Safety Board. Held: 19970429–19970430. 1998. pp. 9–27 (9 Tab., Refs.) PY: 1998. RN: 0865875162. AB: Increasing attention, both nationally and internationally, is being paid to the management of fatigue among all classes of drivers but especially among truck and bus drivers. This paper is divided into two parts. The first part describes research into the question of whether the introduction of driving and related working hours regulations to Western Australia (WA) would be beneficial. To do so, research considered the impact of the proposed regulations on the WA industry; the success of enforcing the regulations in other states; the impact of fatigue on drivers in WA versus the states regulating driving hours; and the effectiveness of self regulation in WA as com- pared with enforcement in other states. It was concluded that there is no evidence that the introduction of prescriptive driv- ing hours into WA would benefit the community, and quite possibly might worsen the problem of fatigue. The second part of the paper describes the WA Government response to the research. AN: 00789167 Hartley, L. SB: IRRD-OECD. TI: Australian initiatives in managing fatigue in transportation. SO: Insurance Commission of Western Australia Conference on Road Safety, 1999, Perth, Western Australia. 1999/11. pp. 124–39 (5 Refs.) PY: 1999. AB: In most developed jurisdictions, fatigue has been addressed by restricting HOS and mandating time off work. In most of Australia, under the Truck Driving Hours Regula- tions, a driver cannot drive more than 12 hr or work more than 14 hr in each 24-hr period, with minimum rest requirements during that period. No more than 72 hr driving or working is possible in a 7-day period, and one continuous 24-hr rest break must be taken away from the truck during this time. There are a number of criticisms of this approach including its lack of flexibility, failure to consider the circadian rhythms of drivers, poor compliance because of the absence of incentives to do

so, poor enforcement because of the difficulties of doing so, and rigid restriction on HOS may prevent drivers reaching better rest facilities only a short distance away. Improved management of fatigue must address these issues. Two Aus- tralian alternatives to the traditional HOS regime are described. (a) For the covering entry of this conference, see ITRD abstract no. E205827. AN: E205836 Haworth, N. SB: IRRD-OECD. TI: Does Regulating Driving Hours Improve Safety? SO: International Conference on Fatigue and Transportation, 3rd, 1998, Fremantle, Western Australia. 1998. 10 p. (17 Refs.) PY: 1998. RN: 0-86905-607-7. AB: Many of those who argue for regulations governing driv- ing hours do so on the basis of ensuring safety standards. The underlying assumption is that limiting the hours of driv- ing per day and per session results in drivers who are more alert and are, therefore, involved in fewer crashes. While this assumption has mass appeal, there is little rigorous support for it. This paper examines the difficulties involved in assess- ing whether regulating driving hours improves safety. The issues and drawbacks involved in comparing the safety per- formance of road transport in currently regulated and unreg- ulated areas are discussed. The characteristics and information requirements of a model which could be developed to test the safety (and cost) implications of having no driving hours reg- ulations or different types of regulations are proposed. (a) For the covering entry of this conference, see IRRD abstract no. 895120. AN: 895129 Horne, J.A. and Reyner, L.A. SB: IRRD-OECD. TI: Falling Asleep at the Wheel. SO: TRL Report. 1995. (168) 26 p. PY: 1995. AB: Certain practical measures to counteract sleepiness under monotonous driving conditions, have been evaluated. Three treatments were given separately during a 30-min rest period between two, 1-hr monotonous drives: a placebo (decaf- feinated coffee), a nap (less than 15 min), and 150-mg caf- feine (in decaffeinated coffee). Ten subjects (experienced drivers) underwent all conditions in a balanced design. Sleep was restricted to 5 hr the night before each treatment condi- tion. An interactive and instrumented driving simulator emu- lated monotonous driving. Subjects drove between 14:00h and 16:30h. Major and minor lane deviations were identified. Subjects reported their subjective alert/sleepiness levels, and recordings were made of brain (EEG) and eye activities (EOGs). Video records showed facial/postural changes. Both caffeine and a nap significantly reduced driving impairments, subjective sleepiness, and EEG activities indicative of drowsi- 106 ness; these effects lasted for the 1 hr duration of driving after treatment. The findings with caffeine were consistent across subjects, whereas those for nap were less so, depending on the ability to nap (most subjects napped). Eye movements (e.g. eye rolling) were unreliable in determining sleepiness and inferior to the other measures. Changes in driving performance and EEG were closely linked, but there was a small time lag between the two. Subjects were aware of their deteriorating EEG state of alertness almost “on line.” Self-knowledge is a good guide to real sleepiness, but subjects may not realise that sleepiness portends sleep, which may descend rapidly there- after. If one has to drive whilst sleepy, then a break with cof- fee or a nap can be beneficial, but only for a while. Hurwitz, J.B. SB: IRRD-OECD. TI: Individual differences in driver risk acceptance during sleep deprivation. SO: International Conference on Traffic and Transport Psy- chology—ICTTP 2000, Held 4–7 September 2000, Berne, Switzerland—Keynotes, Symposia, Thematic Sessions, Work- shops, Posters, List of Participants and Word Viewer—CD ROM. 2001. (26 Refs.) PY: 2001. AB: This paper investigates the role of decisional processes in fatigued drivers. Test subjects were asked to perform a simple computer-based driving task during a period of sleep depriva- tion. Individual performance was simulated using a mathe- matical model of driver risk acceptance. Drivers accept risk by initiating manoeuvres before having sufficient information to determine the consequences. The results suggested that the modeling used could be employed to detect changes in risk taking resulting from sleep loss, and could therefore be useful in developing in-car driver support systems to include coun- termeasures. For the covering abstract, see ITRD E113725. AN: E113860 Janssen, W. SB: IRRD-OECD. TI: How to improve a safe and sustainable driver behav- iour—driver’s fatigue? SO: Safe and Sustainable Transport. A Matter of Quality Assurance. 2003. pp. 107–18 (10 Refs.) PY: 2003. RN: 92-821-1303-5. AB: Reducing the number of accidents that are caused by drowsiness or fatigue could be achieved by applying differ- ent strategies. This paper focuses on the on-line, real-time detection of deteriorating driver state and driving behaviour, and on the question what should be done after this has been detected. It reports three studies performed in the TNO driv- ing simulator. The first one leads to the conclusion that an in- vehicle monitoring device is best based on measures of steering activity, to which the registration of not keeping to one’s lane boundary could be added. The second study points

to the importance of certain personality attributes that deter- mine who is a drowsiness-prone driver. The third study demonstrates that an alertness maintenance device (game- box) can have positive effects on the onset of drowsiness and on the occurrence of critical events that it may cause. Alto- gether the results lead to a positive conclusion with respect to the possibility of implementing a strategy that focuses on the on-line detection of drowsiness and its consequences. Behav- ioural adaptation from the side of the relevant drivers to this strategy, however, is an issue of concern that needs further investigation. For the covering abstract, see ITRD E118917. AN: E118933 Johnson, K. SB: TRB-TRIS. TI: How Many Hours Should a Trucker Drive? SO: Traffic Safety. 2000/03. 00(2) pp. 14–16 (3 Phot.) AB: The National Transportation Safety Board estimates that fatigue is a factor in half of all trucking-related crash fatali- ties annually. The government already has HOS regulations for truckers. The problem is that the rules were put in place in 1939. The Federal Highway Administration is set to release proposed changes to the regulations in spring 2000, with the final version of the new rules released in late 2000 or early 2001. Safety groups and government bodies say changes in HOS should be considered in the context of other relevant factors, including the body’s “internal clock,” payment meth- ods for truck drivers, and driving time records. Current regu- lations say that for every 8 hr a trucker is off-duty, he can drive for 10 hr and work (loading and unloading) for as long as 5 more. A trucking industry newspaper reported that the new regulations would mandate a “14/10” schedule: 14 hr driving, 10 hr off. However, safety groups say that arrange- ment does not give drivers enough time to get home and actu- ally sleep. They favor 12- to 14-hr rest periods with 10- to 12-hr driving limits. AN: 00790606 Khardi, S. SB: IRRD-OECD. TI: Drowsiness of the Driver: EEG (Electroencephalogram) and Vehicle Parameters Interaction. SO: Proceedings of the Fourteenth International Technical Conference on Enhanced Safety of Vehicles, May 23–26, 1994, Munich, Germany. Volume 1. 1995. (94-S3-O-06) pp. 443–61 (75 Refs.) PY: 1995. AB: Three factors are involved in car accidents: the road, the vehicle, and the driver. Of these, the first two have recently received considerable attention; the third factor, the driver behind the wheel, is probably the most important. Attention is paid to the last two factors. The present study characterizes low vigilance periods relative to driver’s drowsiness by simultane- ous analysis of the recorded electroencephalogram (EEG), steering wheel movements, and vehicle speed signals during 107 a 6-hr driving period. The mechanical parameter thresholds of the vehicle are discussed. (a) For the covering abstract of the conference, see IRRD 894848. AN: 894888 King, D.J., Mumford, D.K., and Siegmund, G.P.S.B. IRRD-OECD. TI: An algorithm for detecting heavy-truck driver fatigue from steering wheel motion. SO: Proceedings of 16th International Technical Conference on the Enhanced Safety of Vehicles, Held Windsor, Ontario, Canada, 31 May–4 June 1998. Vol. 2. 1998/10. (DOT HS 808 759) pp. 873–82 (7 Refs.) PY: 1998. AB: This paper is the culmination of previous work to deter- mine if steering behavior could be used to unobtrusively detect driver fatigue. The driving performance of 17 sleep- deprived heavy-truck drivers was monitored on a closed track. Functions in the time, frequency, and phase domains were developed to quantify changes in steering wheel input. The steering-based weighting functions which correlated most strongly with independent measures of driver fatigue and drowsiness were used to develop a simple algorithm. The algo- rithm predicted fatigue for all 17 volunteer drivers before the end of their test. The algorithm identified 12 drivers before a lane breach occurred, and only two drivers were not captured until a lane breach greater than 15-cm occurred. These data and the algorithm demonstrate the potential for a steering-based fatigue detection algorithm. (a) For the covering abstract, see IRRD E102514. AN: E103116 Mabbott, N., Newman, S., and Moore, B. SB: IRRD-OECD. TI: Safety and productivity through flexibility: driving hours review. SO: ARRB Transport Research Ltd. Conference, 20th, 2001, Melbourne, Victoria, Australia. 2001. 19 p. PY: 2001. RN: 0-86910-799-2. AB: A review of the regulatory approach to heavy-vehicle driver fatigue in Australia has now commenced. The review will be led by the NRTC with participation from road authori- ties, the road transport industry, and others. The objective of the policy review is improvements in road safety and transport productivity through the development and implementation of policies and practices to assist in the management of fatigue in drivers of heavy vehicles. Issues to be considered in future policy development include the extent of the problem, results of recent research on circadian rhythms (time-of-day effects) and sleep/rest needs, the desirability of greater operator flexi- bility within safety constraints, the WA approach of a Code of Practice applied under OH&S legislation, and consistency between transport and OH&S requirements. It is likely that proposals for evaluation will involve a flexible range of

options from basic prescription to full fatigue management, all options consistent with the “duty of care” requirements of occupational health and safety legislation, and more wide- spread use of electronic record keeping, possibly as a pre- requisite for increased flexibility. The latter part of this paper presents a summary of a project concerning flexibility options for regulated HOS. (a) For the covering entry of this confer- ence, see ITRD E204173. AN: E204227 Macchi, M.M., Boulos, Z., Ranney, T., Simmons, L., and Campbell, S.S. “Effects of an afternoon nap on nighttime alertness and per- formance in long-haul drivers.” Accident Analysis & Pre- vention. 2002/11. 34(6) 825–834. Mahon, G.L. SB: TRB-TRIS. TI: New Approaches to Fatigue Management: A Regulator’s Perspective. CA: American Trucking Associations, Inc., Alexandria, VA, USA. SO: Conference Title: Managing Fatigue in Transportation. Location: Tampa, Florida. Sponsored by: American Trucking Associations, Association of American Railroads, Federal Highway Administration, Federal Railroad Administration, National Highway Traffic Safety Administration, and National Transportation Safety Board. Held: 19970429–19970430. 1998. pp. 145–153 (Refs.) PY: 1998. RN: 0865875162. AB: The Fatigue Management Program is an initiative by the Queensland Department of Transport to move toward performance-based legislation to manage a major occupa- tional hazard—fatigue—in the road transport industry. The program targets the development and implementation of man- agement training, schedules, and education programs that focus on fatigue and outlines the need for drivers to acquire amounts of quality sleep, develop strategies for avoiding sleep loss, and consider the behavioral and physiological con- sequences of tiredness. This will enhance awareness that sleep can occur suddenly and without warning to all drivers regardless of their age or experience and that fatigue has a serious effect on a driver’s work performance and safety. Successful management of driver fatigue involves a cooper- ative approach between management and their drivers. It is about balancing the fatigue levels of each driver and provid- ing the appropriate countermeasures to alleviate the impact or onset of fatigue. AN: 00789176 Mercier-Buyon, C. (Ed.), Vallet, M., and Khardi, S. SB: IRRD-OECD. TI: Working Conditions and Fatigue Among Lorry Drivers: Alcohol, Drugs and Driving Safety: A Literature Study. 108 SO: Proceedings of the 14th International Conference of Alcohol, Drugs and Traffic—T’97, Held Annecy, France, 21–26 September 1997, Vol. 2. 1997. pp. 587–95 (33 Ref.) PY: 1997. RN: 2-9511746-0-8. AB: Earlier work on the involvement of truck drivers in acci- dents is outlined. The author then examines in more detail evidence of the use of alcohol, medication, and narcotics. It is suggested that these factors may be linked to the working conditions experienced by truck drivers, in particular work duration, sleep deprivation, and fatigue. Attention is drawn to the occurrence of pathological sleeping disorders among pro- fessional drivers. For the covering abstract, see IRRD 893732. AN: 894677 Moore-Ede, M., Heitmann, A., Guttkuhn, R., Trutschel, U., Aguirre, A., and Croke, D. SB: TRB-TRIS. TI: Circadian Alertness Simulator for Fatigue Risk Assess- ment in Transportation: Application to Reduce Frequency and Severity of Truck Accidents. SO: Aviation, Space and Environmental Medicine. 2004/03. 75(3) pp.107–118 (7 Fig., 15 Ref.) PY: 2004. AB: The Circadian Alertness Simulator (CAS) was devel- oped for assessing the risk of diminished alertness at work. The assessment of operational fatigue risk, work schedule optimization, and fatigue-related accident investigation are some of the applications of CAS. Sleep and alertness patterns are estimated based on the documented work schedules and the cumulative fatigue score is calculated. The free parame- ters of the algorithms were optimized using more than 10,000 sleep and alertness datasets collected from transportation workers performing their regular jobs. Heavy truck drivers involved in DOT-recordable or high-cost accidents were found to have significantly higher CAS fatigue risk scores than acci- dent free drivers. Further examination of CAS risk assess- ment validity using scenarios provided in a fatigue modeling workshop indicated that the CAS model performed well in estimating alertness with a real-world transportation scenario of railroad locomotive engineer work-rest patterns. AN: 00972989 Parrott, S. SB: IRRD-OECD. TI: Dead tired. SO: Commercial Motor. 2000/02/03/09. 191(4860) pp. 44–5. AB: According to recent researches, driver fatigue is blamed for 10% of all road accidents and up to 20% of motorway accidents in the United Kingdom; 25% of lorry drivers suffer from dangerous levels of fatigue on the road because they are too busy to take a break. This article discusses whether and to what extent their employers are to blame. Anyone in charge of a vehicle weighing at least 3.5 tons is liable to the EU driv- ers’ hours laws, which limit driving time to 10 hr per day for

2 days per week and 9 hr per day for other days, and specify required rest periods. Unfortunately, there are several ways of distorting driving records made by tachographs, and law enforcement has at least one loophole. At present, transport is not yet covered by the EU Working Time Directive, which became law in the United Kingdom 1 October 1998 and lim- its the average working week to 48 hr, although the Transport & General Workers Union is urging an extension of this law. A questionnaire was sent to 220 drivers and 420 managers of lorries, asking them about their driving hours and breaks in relation to tiredness; the 720 replies showed quite high rates of bad practices. In January 2000, the road safety campaign group Brake held a conference for transport professionals concerned about fatigue, which produced useful advice for employers. AN: E104633 Peters, R. D. Effects of partial and total sleep deprivation on driving performance. Proceedings from Human Factors and Ergonomics Society, Santa Monica, CA. Human Factors and Ergonomics Society Inc., 1995. Vol. 2, 935. AB: The National Highway Traffic Safety Administration estimates that from 1989 through 1993, driver drowsiness/ fatigue was a contributing factor in 100,000 crashes annually on U.S. highways. A recent study examined the effects of progressive sleep deprivation on driving performance to assess the rate of crashes and the changes in driving perfor- mance resulting from sleepiness. Because it would be unsafe to study this under real driving conditions, the high-fidelity highway driving simulator was used. A variety of measures, including continuous EEG monitoring, videotaping, and analy- ses of driving performance data and questionnaire data were used to determine the effects of sleep deprivation on the driv- ing performance of six men and six women aged 26 to 35. Highway safety variables, including number of crashes and number of lane excursions, were unacceptably high on day 3 after 36 hr of no sleep and on day 4 after 60 hr without sleep. More subtle measures of highway safety such as speed and lateral placement variance were also linked to sleep depriva- tion. Although some trends appeared, none of the variables were significantly affected by partial sleep deprivation, per- haps because participants were young, very healthy, non- medicated and because they had no sleep debt at the start of the study. A preliminary neural net analysis using the data collected is underway. If patterns of driving performance can be identified, it will lend strong support for the development of a neural net in-vehicle-based system for detecting and warning drowsy drivers of potential danger. Peters, R., Thomas, M., Welsh, A., Alicandri, E., Thorne, D., Sing, H., Wagner, E., and Belenki, G. SB: TRB-TRIS. TI: Fatigue-Related Accidents: What Really Happens Prior to a Crash? CA: Human Factors and Ergonomics Society, Inc., Santa Monica, CA, USA. 109 SO: Conference Title: Human Factors and Ergonomics Soci- ety 42nd Annual Meeting, Proceedings. Location: Chicago, IL. Sponsored by: Human Factors and Ergonomics Society. Held: 19981005–19981009. 1998. 2 pp. PY: 1998. RN: 0945289111. AB: Official statistics indicate a trend toward an increase in fatigue-related accidents over the past 5 years. It is widely believed that these official statistics grossly underestimate the role of fatigue in accidents. This collaborative study defined performance decrements that drivers experience under vary- ing levels of partial and total sleep deprivation. A 4 (rested, partial, 36-hr, and 60-hr sleep deprivation) by 8 (type of road- way) by 2 (gender) mixed factorial design with repeated measures of driving performance in a high fidelity driving simulator was used to define these performance decrements. Analyses revealed several driving performance measures were significantly affected by sleep deprivation including number of crashes, lateral placement variance, speed, and lane excur- sions. Regression analyses showed that lateral placement variance was the best predictor of crashes. The most surpris- ing finding was that most crashes were not directly preceded by microsleep events (defined here as 1 to 15 seconds of stage 1 sleep). It has long been assumed that in most circumstances, drowsy drivers have gotten into accidents by falling asleep, but this finding refutes that belief. Drowsy driver crashes may, in fact, be more directly related to the inattention and distractibility that accompany sleep deprivation than to falling asleep at the wheel. AN: 00767979 Peters, R.D., Wagner, E.K., Alicandri, E., Fox, J.E., Thomas, M.L., Thorne, D.R., Sing, H.C., and Balwinski, S.M. “Effects of partial and total sleep deprivation on driving perfor- mance.” (1999). Public Roads. 62(4) 2–6. Ranney, T.A., Simmons, L.A., Boulos, Z. and Macchi, M.M. SB: TRB-TRIS. TI: Effect of an Afternoon Nap on Nighttime Performance in a Driving Simulator. SO: Transportation Research Record. 1999. (1686) pp. 49–56 (4 Fig., 2 Tab., 32 Ref.) PY: 1999. RN: 0309071135. Riley, M.W., Stentz, T.L. and Tarawneh, I. SB: TRB-TRIS. TI: Safety Impact Issues of Job-Associated Sleep. CA: University of Nebraska, Lincoln, USA; Somnos Labo- ratories, Lincoln, NE, USA. SO: 1997/09. pp. 127 (Tabs., Apps.) PY: 1997. RN: Report Number: MATC UNL96-2; Contract/Grant Num- ber: DTRS95-G-0007. AB: This research investigated the safety impact issues of job-associated sleep in truck drivers. The research focused on

the anonymous survey of professional truck drivers. Infor- mation was gathered regarding perception of driving perfor- mance and its relationship to sleep on the road. In addition to the survey, detailed information was gathered on a typical sleeper berth used by 65% of the respondents. All recom- mendations address issues that were identified by less than 85% of the respondents in the questionnaire. Thus, the poten- tial impact of these recommendations can be low due to the small response sample of professional drivers. First, drivers should be medically screened and treated if necessary for sleep disorders. Second, special training and education is needed to help drivers improve their strategies to overcome fatigue and obtain more and better quantity sleep. Third, the presence of sleep deprivation in drivers, as a result of many contributing factors, indicates a need for a comprehensive design model for work-rest cycle planning. Fourth, the phys- ical discomforts reported by drivers need additional investi- gation to determine the sources of exposure in order to facilitate exposure elimination or reduction. AN: 00789661 Rothengatter, T. (Ed.), Carbonell-Vaya, E. (Ed.), Desmond, P.A., and Matthews, G. SB: IRRD-OECD. TI: The Role of Motivation in Fatigue-Related Decrements in Simulated Driving Performance. SO: Traffic and Transport psychology. Theory and Applica- tion. 1997. pp. 325–34. PY: 1997. RN: 0-08-042786-3. AB: The role of the driver’s motivational state in eliciting fatigue-related decrements in driving performance has been largely neglected by researchers. However, its importance has been highlighted by McDonald (1984), who argues for motivational explanations for impairments in decisionmak- ing, judgment of risk and attention when driving is prolonged. Studies of fatigue in contexts other than driving also indicate that de-motivation and apathy are primary symptoms of fatigue, which are expressed in reduced effort on the task at hand (Craig and Cooper 1992). Hence the aim of the present study was to examine the effect of a motivational manipula- tion in reversing or reducing fatigue-related decrements in simulated driving performance. The authors also aimed to examine implications of motivational change for the design and use of in-vehicle countermeasures to driver fatigue. As in the Desmond and Matthews (1996) study, drivers per- formed both a fatiguing drive, in the first part of which a fatigue induction procedure was added to the primary task of driving, and a control drive without fatigue induction. The effects of the fatigue manipulation on drivers’ subjective states were assessed by the selection of subjective measures used in the previous study. The motivational manipulation, an instruction that driving skill was under assessment, appeared in early and late stages of control and fatigue drives. Control of the lateral position of the vehicle was assessed 110 before, during, and after the instruction. For the covering abstract, see IRRD 896859. AN: 899040 Status Report. 2004/08/01. 39(7) pp. 2–3 (1 Phot.) SB: TRB-TRIS. TI: Try Again on Rules Governing Truck Driving Hours, Court of Appeals Tells FMCSA. PY: 2004. AB: The U.S. Court of Appeals has decided that rules issued by the Federal Motor Carrier Safety Administration (FMCSA) fail to take into consideration the safety and health of truck drivers. While FMCSAs proposed rules would have required a longer rest period between stretches of driving, they would also have extended the maximum allowable driving time and would not have required onboard recorders to monitor truck- ers hours of driving. The Court questioned the rationality of the FMCSA and specified that the agency focus on the safety of truck drivers rather than on promoting the economic well- being of the motor carrier industry. AN: 00978338 Steinberg, C. SB: TRB-TRIS To Health Group. TI: A Study of Prevalence of Sleep Apnea among Commer- cial Truck Drivers. SO: Tech Brief. 2002/07. pp. 4 (1 Ref.) PY: 2002. RN: Report Number: FMCSA-RT-02-080. AB: Staying awake means staying alive. This is a slogan used to describe a research study on sleep apnea sponsored by the FMCSA and the American Transportation Research Institute of the American Trucking Associations. The research project addressed the prevalence of sleep apnea among CMV drivers, potential risk factors, and its impact on driving performance. This tech brief summarizes the project’s final report, “A Study of Prevalence of Sleep Apnea Among Commercial Truck Drivers.” AN: 00932082 Stutts, J.C., Wilkins, J.W., and Vaughn, B.V. SB: TRB-TRIS. TI: Causes of Sleepiness in Drivers Who Crash. CA: Association for the Advancement of Automotive Medi- cine, Barrington, IL, USA. SO: Conference Title: Association for the Advancement of Automotive Medicine 45th Annual Proceedings. Location: San Antonio, Texas. Sponsored by: Association for the Advance- ment of Automotive Medicine. Held: 20010924–20010926. 2001. pp. 416–419 (3 Fig.) PY: 2001. RN: Report Number: Scientific poster. AB: For the large majority of the driving public, sleepiness is likely due to one of three causes: not getting enough sleep on a routine basis; getting much less sleep than needed on a

short-term or single night basis; or not sleeping when one’s biological clock is programmed to sleep. These three causes are the focus of the current study. Population-based samples of drivers in recent crashes were identified from North Car- olina crash report forms as they were received at the Division of Motor Vehicles office in Raleigh, North Carolina. All cases in which the driver of a vehicle was coded as either “asleep” or “fatigued” by the investigating officer were iden- tified, along with a random sample of control crash drivers. The identified drivers were then contacted for telephone inter- views to obtain information on their work/sleep schedules and circumstances surrounding their crashes. Chronic sleep loss, acute sleep loss, and nighttime sleep disruption were all found to be important contributors to sleep-related motor vehicle crashes. Although certain segments of the population, including shift workers and persons with undiagnosed sleep disorders, are known to be at high risk for involvement in sleep-related motor vehicle crashes, the vast majority of such crashes involve individuals who either do not get enough sleep on a regular basis, got far too little sleep the night before their crash, and/or were trying to drive when their biological clocks were programmed for sleep. AN: 00923459 Tech Brief. 1998/10. pp. 4 (1 Fig., 1 Tab., 1 Ref.) SB: TRB-TRIS. TI: PERCLOS: A Valid Psychophysiological Measure of Alertness as Assessed by Psychomotor Vigilance. PY: 1998. RN: Report Number: FHWA-MCRT-98-006. AB: This tech brief summarizes an Intelligent Transportation System (ITS) study titled “Evaluation of Techniques for Ocu- lar Measurement as an Index of Fatigue and as the Basis for Alertness Management.” The study was funded in part by the FHWA’s Office of Motor Carriers and managed by the National Highway Traffic Safety Administration (NHTSA). The project’s goal was to evaluate the validity and reliability of several drowsiness-detection measures and technologies in a controlled laboratory setting and to analyze the effects of alerting stimuli on drivers’ alertness levels. Of the drowsiness- detection measures and technologies evaluated in this study, the measure referred to as “PERCLOS” was found to be the most reliable and valid determination of a driver’s alertness level. PERCLOS is the percentage of eyelid closure over the pupil over time and reflects slow eyelid closures (“droops”) rather than blinks. A PERCLOS drowsiness met- ric was established in a 1994 driving simulator study as the proportion of time in 1 min that the eyes are at least 80% closed. FHWA and NHTSA consider PERCLOS to be among the most promising known real-time measures of alertness for in-vehicle drowsiness-detection systems. The results of this research support the development of a “first-ever” real- time drowsiness detection sensor that would measure the per- centage of eyelid closure over the pupil, over time (i.e., PERCLOS). AN: 00760599 111 Tech Brief, 1999/04. Eye-activity measures of fatigue and napping as a fatigue countermeasure. FHWA-MCRT-99-010. Tech Brief. 1999/08. pp. 4 (3 Fig.) SB: TRB-TRIS. TI: Eye-Activity Measures of Fatigue and Napping as a Fatigue Countermeasure. PY: 1999. RN: Report Number: FHWA-MCRT-99-010. AB: CMV driver inattention, particularly that due to fatigue, is widely recognized as an important safety issue in the trans- portation industry. This tech brief summarizes an Office of Motor Carrier and Highway Safety study to investigate the potential of an eye tracking system for detecting reduced driver alertness and to determine the impact of preventative napping on driver alertness and performance. The complete final report will be available from the National Technical Information Service. AN: 00789191 Tech Brief. 2000/01. pp. 4 (1 Phot.) SB: TRB-TRIS. TI: Driver Alertness and Fatigue: Summary of Completed Research Projects, 1995–98. RN: Report Number: FMCSA-MCRT-00-006. AB: This document describes projects in the FMCSA’s Driver Alertness and Fatigue Research and Technology (R&T) focus area that were completed during the years 1995 to 1998 under the former Office of Motor Carriers in the FHWA. The projects covered in this tech brief include Driver Fatigue and Alertness Study, Fitness-for-Duty Testing, CMV Rest Areas—Making Space for Safety, Multi-Trailer Combination Vehicle Stress and Fatigue, Validation of Eye and Other Psychophysiological Monitors, Local/Short Haul Driver Fatigue Crash Data Analysis, Shipper Involvement in HOS Violations, and Assessment of Electronic On-Board Recorders for HOS Compliance. In addition, 3 conferences dealing with driver fatigue are described. AN: 00789182 Van Schagen, I. SB: IRRD-OECD. TI: Fatigue while driving: inventory of causes, effects, and measures. (Vermoeidheid achter het stuur: een inventarisatie van oorzaken, gevolgen en maatregelen.) SO: 2003. (R-2003-16) 45 p. (67 Refs.) PY: 2003. AB: Also in the Netherlands there is an increasing awareness that driving while tired is an important factor in the occur- rence of road accidents. This literature study aims at provid- ing an overview of the knowledge and insights about the relationship between fatigue and road safety. The study shows that fatigue has many more causes than the time somebody

has been driving. Too little sleep or a poor quality sleep, the time of day, and stress situations all contribute to the occur- rence of fatigue. Determining the extent to which fatigue plays a part in accidents occurring is extremely awkward. It is almost impossible to objectively diagnose fatigue. When the various foreign data sources are combined, it must be con- cluded that fatigue is a (partial) cause in 10 to 15% of all severe accidents. There is no reason to suppose that in the Netherlands this percentage is substantially different. The short-term possibilities of taking measures to reduce the num- ber of fatigue-related accidents are limited, especially for the “normal” car driver. The only thing that can be done at the moment is in the sphere of information. In addition, for pro- fessional drivers, there are legal possibilities concerning driv- ing hours, duration, and rest periods and their enforcement, but there is also the possibility of starting so-called fatigue management programs and propagating a safety culture within haulage companies. In the more distant future, there are pos- sibilities in the sphere of intelligent systems that automati- cally detect and, if necessary, intervene. There are various promising developments, but their large-scale application will take some time. This report may be accessed by Internet users at: http://www.swov.nl/rapport/ R-2003-16.pdf. AN: E206767 Van Winsum, W. SB: IRRD-OECD. TI: Age-related differences in effects of drowsiness on mea- sures of driver behaviour and performance. SO: 1999/01/05. (TM-99-C001) 23p (18 Refs.) PY: 1999. AB: In a driving simulator, the effects of time on task were measured on variables that measure drowsiness, driving per- formance, and steering behavior for groups of younger and older drivers. It was found that the fraction of time during which the eyes were closed is a good measure of drowsiness that is sensitive to the effects of time on task. Of all single variables that measure driver performance and impairment, the percentage of time during which any part of the vehicle exceeded one of the lane boundaries was the most strongly affected by time on task. Also, with progressing drowsiness, the amplitude of steering corrections increased toward larger values. This was caused both by larger error corrections in response to larger errors and by an increase in coarseness of the steering response. Large steering corrections proved to be the single best indicator of progressing impairment by drowsi- ness and fatigue. Older drivers performed poorer on lateral control of the vehicle compared with younger drivers. Also, driving performance of older drivers deteriorated more with time on task compared with younger drivers. However, there were no differences between younger and older drivers in the reliability and validity of the different measures for drowsi- ness, steering behavior, or driving performance. 112 Watson, G.S., Weiler, J.M., Woodworth, G.G., Qidwai, J.C., and Quinn, S.A. SB: IRRD-OECD. TI: An analysis of driving performance measures used to assess the effects of medications on drowsiness, sedation, and driving impairment. SO: Proceedings of the First International Driving Sympo- sium on Human Factors in Driver Assessment, Training, and Vehicle Design, Held Aspen, Colorado, August 14–17, 2001. pp. 252. PY: 2001. AB: The objective of this paper was to discuss driving sce- narios and associated driving performance measures on their ability to demonstrate drowsiness, sedation, and driving impairment. The basis of this paper was a study that utilized a randomized, double-blind, double-dummy, four-treatment, four-period crossover trial in the Iowa Driving Simulator (IDS). Participants were 40 licensed drivers with seasonal allergic rhinitis who were 25 to 44 years of age. Treatments were Fexofenadine, diphenhydramine, alcohol, or placebo, given at weekly intervals before participants drove for 1 hr in the IDS. Measures examined included coherence, amplitude, phase angle, RMS error, following distance and behavior, lane keeping, response to unexpected vehicle intrusion, and drowsiness. Study results show that sedating antihistamines impair driving performance as seriously as alcohol. Statisti- cally significant but small correlations were found between subjective drowsiness and minimum following distance, steer- ing instability, and left-lane excursions but no correlation was greater than 0.21. Drowsiness was a weak predictor of driv- ing impairment. This paper discusses these and other find- ings with an emphasis on the adequacy of driving scenarios and the sensitivity of driving performance measures analyzed. For the covering abstract, see ITRD E113119. AN: E113161 Williamson, A., Feyer, A.M., Friswell, R., and Finlay- Brown, S. SB: IRRD-OECD. TI: Development of measures of fatigue: using an alcohol comparison to validate the effects of fatigue on performance. SO: Report. 2000/07. (CR 189) 72 p. PY: 2000. RN: 0-642-25579-2. AB: This study was the first of a series looking at the devel- opment of model work-rest schedules that have demonstrated effectiveness in managing driver fatigue. The aim was to develop a range of performance tests with demonstrated sen- sitivity for fatigue and for which the fatigue effects could be interpreted on the basis of a community-accepted standard for safety. Performance effects were studied in the same sub- jects over a period of 28 hr of sleep deprivation and follow- ing measured doses of alcohol up to approximately 0.1% BAC. Subjects were 39 employees from the transport industry

and the army. After 17 to 19 hr without sleep, corresponding to approximately 10:30 p.m. and just after midnight, perfor- mance on some tests was equivalent or worse than that at 0.05% BAC. Response speeds were up to 50% slower for some tests and accuracy measures were significantly poorer at this level of alcohol. After longer periods without sleep, per- formance reached levels equivalent to the maximum alcohol dose given to subjects (0.1% BAC). The results also demon- strated that not all types of performance tests were affected by sleep deprivation. Also, differences between the performance of drivers and controls suggested that drivers took a more con- servative approach to performance. This study demonstrated which of a set of performance tests can be used in evaluations of fatigue and fatigue countermeasures. The findings also rein- force evidence that the fatigue of sleep deprivation is impor- tant and likely to compromise speed and accuracy needed for safety on the road and in other industrial settings. AN: E204278 Williamson, A.M., Feyer, A.M., Mattick, R.P., Friswell, R., and Finlay-Brown, S. SB: IRRD-OECD. TI: Developing measures of fatigue using an alcohol com- parison to validate the effects of fatigue on performance. SO: Accident Analysis & Prevention. 2001/05. 33(3) pp. 313–26 (40 Refs.) PY: 2001. AB: The effects of 28 hr of sleep deprivation were compared with varying doses of alcohol up to 0.1% BAC in the same subjects. The study was conducted in the laboratory. Twenty long-haul truck drivers and 19 people not employed as pro- fessional drivers acted as subjects. Tests were selected that were likely to be affected by fatigue, including simple reac- tion time, unstable tracking, dual task, Mackworth clock vig- 113 ilance test, symbol digit coding, visual search, sequential spa- tial memory, and logical reasoning. While performance effects were seen due to alcohol for all tests, sleep depriva- tion affected performance on most tests, but had no effect on performance on the visual search and logical reasoning tests. Some tests showed evidence of a circadian rhythm effect on performance, in particular, simple reaction time, dual task, Mackworth clock vigilance, and symbol digit coding, but only for response speed and not response accuracy. Drivers were slower but more accurate than controls on the symbol digit test, suggesting that they took a more conservative approach to performance of this test. This study demonstrated which tests are most sensitive to sleep deprivation and fatigue. The study therefore has established a set of tests that can be used in evaluations of fatigue and fatigue counter- measures. Yarrow, R. SB: IRRD-OECD. TI: Wake up call. SO: Auto Express. 2000/11/22. (629) pp. 35–6. PY: 2000. AB: The results are detailed of a trial carried out at the Sleep Research Centre, Loughborough University, into the effects of caffeine-packed soft drinks on sleepy drivers. According to the Department of Environment, Transport and Regions’ statistics, 1 in 10 of all accidents on UK roads are caused by people falling asleep with 1 in 5 of accidents on motorways. The trial consisted of fifteen sleep-deprived drivers being tested in a car simulator. The results show the effects on driv- ing performance of sleep-deprivation and how taking a high- energy soft drink can virtually overcome the effects of a lack of sleep for a limited time. AN: E108633

115 (I) Literature Review on Health- Related Issues Associated with Hours of Work Literature review of the body of scientific research concerning HOS and CMV operator health. The purpose of the literature review is to provide information that clearly discusses in a scientific, experi- mental, and quantitative way the relationship between the hours a person works or the structure of the work schedule (on-duty/off-duty cycles, sleep time, etc.) and the impact on some medical conditions. The search should be limited to studies conducted in the United States, Canada, Australia, or European Union on CMV operators on interstate highways, transit systems, aviation, and maritime trans- portation. Studies that do not correspond to these specifications can be included in the review if the panel deems them important for under- standing specific scientific developments. The results of the review shall be presented in language understandable to a non-subject mat- ter expert. Period to be covered: 1975 to present Suggested topics to be covered (1) CV Operator (2) CV Operator Health Issues (3) Age and gender (4) Lifestyle (e.g., exercise, diet) (5) Driving hours (6) Duration of workweeks (7) Length of sleep time and sleep deprivation (8) Shift work (9) Schedule regularity and irregularity (10) Exposure to harmful/toxic substances (11) Occupational health: cardiovascular (e.g., blood pressure), immune system, diabetes, gastrointestinal, musculoskeletal (e.g., lower back pain, sciatica), hearing and vision, mental health, sleep disorders, obesity, sleep apnea Additional questions (a) Is there any scientific literature that addresses specifically the relationship between number of driving hours above a certain threshold and operator’s health issues? (b) Is there any scientific literature addressing health concerns in the areas of musculoskeletal, vibration, noise, blood pressure, as manifested in the 11th hour of driving? (c) Is there any scientific literature addressing gender-specific reac- tion to some conditions, such as environmental heat? Suggested panel leader Michael Belzer or Gerald Krueger APPENDIX A PROJECT STATEMENT OF WORK Suggested panel members * Roger Rosa, PhD. (NIOSH): Shift work * Ellison Wittels, MD: Cardiovascular: * John Sheridan, PhD.: Diabetes (John leads FMCSA support ser- vices contractor team on the diabetes program) * Melvyn Sterling, MD: Gastrointestinal, musculoskeletal, hearing * Gerald Krueger, PhD., and James W. Curran, MD: Wellness * Lee Husting or Stephanie Pratt (both of NIOSH): Occupational safety * Peter Orris, MD and Toni Alterman (NIOSH): Occupational health * Kenneth Wells, MD: Mental health * David Dinges, PhD. (University of Pennsylvania): Sleep disorders (II) Literature Review on Fatigue Issues Associated with Hours of Work Literature review of the body of scientific research concerning HOS and CMV operator performance and fatigue health. The purpose of the literature review is to provide information that clearly discusses in a scientific, experimental, and quantitative way the relationship between the hours a person works or the structure of the work sched- ule (on-duty/off-duty cycles, time on task, sleep time, etc.) and the impact on driver fatigue and performance. The search should be lim- ited to studies conducted in the United States, Canada, Australia, and European Union on CMV operators on interstate highways, tran- sit systems, aviation, and maritime transportation. Studies that do not correspond to these specifications can be included in the review if the panel deems them important for understanding specific scien- tific developments. The results of the review shall be presented in language understandable to a non-subject matter expert. Period to be covered: 1995 to present Suggested topics to be covered (1) CMV Operator (2) CMV Operator Performance Issues (3) Age and gender (4) Lifestyle (e.g., exercise, diet) (5) Driving hours (6) Duration of work weeks (7) Length of sleep time and sleep deprivation (8) Shift work (9) Time on task (10) Schedule regularity and irregularity (11) Exposure to harmful/toxic substances (12) Sleep deprivation countermeasures, e.g., naps (13) Hours-of-service regulations: general considerations, sched- ules, shift rotation, multi-day shifts, outcomes of pilot tests and waivers, operational and performance models (14) Technological approaches to CMV driver alertness management

(15) Personal wellness (16) Alertness (17) Fatigue (18) Distraction (19) Reaction time Additional questions (a) Is there any scientific literature that addresses specifically the relationship between number of driving hours above a certain threshold and operator’s fatigue? (b) Is there any research that shows how fatigue builds or does not build under certain conditions or scenarios, e.g., 11/14 hr driving/working days, working more than 60 hr in 7 days? (c) Is there any scientific literature that focuses on the impact on fatigue of splitting the sleep time into shorter periods? (d) Are there documented differences in the quality of sleep between when the truck is parked vs. when the truck is in motion? (e) Is there research on the definition of a cumulative fatigue factor and the factors that affect it?? Suggested panel leader Alison Smiley, Transport Canada Suggested panel members * David Dinges, PhD. (University of Pennsylvania): Sleep disorders * Roger Rosa, PhD. (NIOSH): Shift work * Ellison Wittels, MD: Cardiovascular: * Gerald Krueger, PhD., and James W. Curran, MD: Wellness * Lee Husting or Stephanie Pratt (both of NIOSH): Occupational safety * Peter Orris, MD and Toni Alterman (NIOSH): Occupational health * Kenneth Wells, MD: Mental health * Gregory Belenky, PhD. * Tom Dingus, PhD. (VTTI) * Merrill Mitler Note: There are several experts on both panels because they repre- sent suggestions coming from FMCSA. The panel leader will choose 116 the actual panel members based on their knowledge and on the expert’s availability. It is expected that there would be three people on each panel in addition to the panel leader. Suggested process for each review 1. Preparation (Weeks 1 and 2) 1.1. The panel leader meets with FMCSA to clarify the scope of the literature review 1.2. Based on the suggestions received from FMCSA and his/her own knowledge, the Panel leader forms a panel of experts that will support the literature review 1.3. The panel leaders develop an outline of the Literature Review Report 1.4. The panel leader reports progress to FMCSA and gets consensus on the outline 2. Development of preliminary findings (Weeks 2 through 8) 2.1. The panel leader, with the support of the experts of the panel, assembles a list of papers for the literature review 2.2. The panel leader summarizes the most significant papers on the list and prepares an interim report with preliminary findings 2.3. FMCSA reviews the interim report and provides feed- back to the panel leader and to the panel of experts on the continuation of the effort 3. Development of the literature review report (Weeks 8 through 12) 3.1. The panel leader develops, with the help of the panel members, the draft literature review according to the agreed outline 3.2. The panel leader sends the draft to the panelists for com- ment and integration 3.3. The panel leader updates the draft 3.4. The panel leader presents the draft to FMCSA 3.5. FMCSA reviews the draft and provides comments 4. Development of the final version of the literature review report (Weeks 12 through 14) 4.1. The panel leader updates, with the help of the panel mem- bers, the draft literature review 4.2. The panel leader briefs FMCSA on the findings and delivers the final version to FMCSA

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TRB’s Commercial Truck and Bus Safety Synthesis Program (CTBSSP) Synthesis 9: Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work examines literature relevant to health and fatigue issues associated with commercial vehicle driver hours of service. This literature review was specifically requested by the Federal Motor Carrier Safety Administration (FMCSA) to provide information related to its Hours of Service regulations issued in January 2004. The report contains a general literature review of the health issues from 1975 to the present, and fatigue issues from January 2004 to present, associated with commercial vehicle driver hours of service. The report also contains a literature review of references that were cited in response to a related FMCSA January 2005 Notice of Proposed Rulemaking. Strictly a literature review, the report does not contain any conclusions or recommendations.

CTBSSP Synthesis 9 Errata Sheet -- Some citation information and abstracts were inadvertently omitted from CTBSSP Synthesis 9 as published.

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