The National Academies Press

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Pages 64-78

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From page 64... ... Of all the factors, contributing factors are the key in the study of driver behavior and were judged by trained data reductionists to have directly influenced the presence or severity of a crash or near crash. Three subcategories were further constructed for contributing factors to identify the causes of crashes: infrastructure factors and driving environment factors, such as road surface, traffic density, and weather; driver factors, such as driver inattention, drowsiness, and distraction; and vehicle factors, such as flat tires and vehicle breakdowns.64As revealed by the data, the factors that contributed to a crash usually were not caused by a sole factor but involved some form of factor interaction. Read the entire page →
From page 65... ... Contributing Factors for Crashes in Project 6 Factor Category Crashes Total Number Driver Environmental Vehicle Single vehicle 24 121% 38% 0% Lead vehicle 15 127% 13% 0% Following vehicle 12 83% 8% 0% Object obstacle 9 144% 56% 0% Parked vehicle 4 100% 50% 0% Animal 2 0% 100% 0% Turning across opposite direction 2 100% 50% 0% Adjacent vehicle 1 100% 0% 0%from equipped vehicles. The most frequent critical reason for crashes was "object in roadway," which constituted 57% of the total events. Read the entire page →
From page 66... ... Critical Factors Contributing to Crashes and Near Crashes Critical Factor Crashes Near Crashes Driver-related factor (critical nonperformance errors) , including sleep; heart attack or other physical impairment of the ability to act; drowsiness, fatigue, or other reduced alertness; other critical nonperformance 8 (11.6%) Read the entire page →
From page 67... ... The most frequently suggested functional countermeasures relating to modifying driver behavior include increasing driver recognition of specific highway crash threats (improving driver recognition of forward threats) , increasing driver attention, improving driver situation awareness, and defensive driving. Read the entire page →
From page 68... ... ; other or unknown recognition error Driver-related factor (decision errors) , including too fast or too slow; misjudgment 1 20% 1 12.5% 6 9.8% of gap; following too closely or unable to respond to unexpected actions; false assumption of other road user's actions; apparently intentional sign or signal violation; illegal U-turn or other illegal maneuver; failure to turn on headlamps; inadequate evasive action; aggressive driving; other or unknown decision error Driver-related factor (performance errors) Read the entire page →
From page 69... ... Increase driver recognition of specific highway crash threats: vehicle in right adjacent lane 0 0.0% 0 0.0% 0 0.0% during merging maneuver 21. Increase driver recognition or gap judgment recrossing or oncoming traffic at intersections 0 0.0% 0 0.0% 0 0.0% 22. Read the entire page →
From page 70... ... 0 0.0% 0 0.0% 0 0.0% 32. Improve driver recognition or gap judgment relating to oncoming vehicle during 0 0.0% 0 0.0% 0 0.0% passing maneuver 33. Read the entire page →
From page 71... ... Increase driver recognition of specific highway crash threats: vehicle in right adjacent 0 0.0% 0 0.0% 0 0.0% lane during merging maneuver 23. Increase driver recognition or gap judgment regarding crossing or oncoming traffic 0 0.0% 0 0.0% 1 1.0% at intersections 25. Read the entire page →
From page 72... ... 0 0% 0 0% 3 5% in lane ahead, traveling in same direction 17. Increase driver recognition of specific highway crash threats: vehicle in left adjacent lane 0 0% 0 0% 9 15% on highway 18. Read the entire page →
From page 73... ... Increase driver recognition or gap judgment regarding crossing or oncoming traffic 0 0% 0 0% 0 0% at intersections 22. Improve driver response execution of crossing or turning maneuver at intersections 0 0% 1 13% 0 0% (performance failure) Read the entire page →
From page 74... ... crashes and near crashes. Read the entire page →
From page 75... ... 50. Roll Rate, x axis fast: Vehicle angular velocity around the longitudinal axis. Read the entire page →
From page 76... ... 71. Yaw Rate, z axis fast: Vehicle angular velocity around the vertical axis. Read the entire page →
From page 77... ... Sixth, additional analysis of existing data is required to study typical levels of variability in driver departure times, typical levels of variability in trip travel times, and the level of variability in driver route choices. A characterization of this behavior is critical in attempting to quantify and develop travel time reliability measures because it identifies potential causes for travel time variability and thus can enhance travel time reliability models. Read the entire page →
From page 78... ... 4. University of Michigan Transportation Research Institute. Read the entire page →

From page 64...

... Of all the factors, contributing factors are the key in the study of driver behavior and were judged by trained data reductionists to have directly influenced the presence or severity of a crash or near crash. Three subcategories were further constructed for contributing factors to identify the causes of crashes: infrastructure factors and driving environment factors, such as road surface, traffic density, and weather; driver factors, such as driver inattention, drowsiness, and distraction; and vehicle factors, such as flat tires and vehicle breakdowns.64As revealed by the data, the factors that contributed to a crash usually were not caused by a sole factor but involved some form of factor interaction.