Human Factors Guidelines for Road Systems: Second Edition (2012) / Chapter Skim
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Pages 107-119
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From page 107... ...
Overview of Work Zone Crashes .
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From page 108... ...
HFG CONSTRUCTION AND WORK ZONES Version 2.0 13-2 O VE RV IE W OF W OR K Z ON E C RA SH ES In tr od uc ti on This guideline provides a framework for characterizing work zone crashe s and, by extension, provides guidelines for work zone design. It specifies the need for additional driver guidance in work zones based on the number, type and severity of crashes occurring in work zones.
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From page 109... ...
13-3 HFG CONSTRUCTION AND WORK ZONES Version 2.0 Di scu ssi on In discussions of work zone crashes, so me research sources provide specific inform ation about the driver behaviors related to crashes, in addition to the characteristics of overrepresented drivers (e.g., age, gender, etc)
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From page 110... ...
HFG CONSTRUCTION AND WORK ZONES Version 2.0 13-4 PROCEDURES TO ENSURE PROPER ARROW PANELVISIBILITY Introduction Arrow panel visibility depends on a number of factors, including the capability of the lamps in the panel, the type of roadway, the physical location of the panel, the panel's relation to horizontal and vertical curves, ambient light, and weather. Procedures to ensure arrow panel visibility should include specifications for the arrow panel as well as field procedures to check in-service arrow panels.
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13-5 HFG CONSTRUCTION AND WORK ZONES Version 2.0 Discussion Human factors studies conducted as part of this research are discussed in detail in Knapp and Pain (2)
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From page 112... ...
HFG CONSTRUCTION AND WORK ZONES Version 2.0 13-6 CAUTION MODE CONFIGURATION FOR ARROW PANELS Introduction This guideline provides recommendations for how to use the arrow panel Caution Mode configuration during temporary traffic control (1)
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From page 113... ...
13-7 HFG CONSTRUCTION AND WORK ZONES Version 2.0 Discussion Caution Mode usage: The Caution Mode configuration should be used when directional information is not warranted (e.g., no merge is necessary) , such as for shoulder work, blocking the shoulder, or roadside work near the shoulder (1)
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From page 114... ...
HFG CONSTRUCTION AND WORK ZONES Version 2.0 13-8 CHANGEABLE MESSAGE SIGNS Introduction Changeable message signs (CMSs) are electronic, reconfigurable signs placed above or near the roadway.
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13-9 HFG CONSTRUCTION AND WORK ZONES Version 2.0 Discussion Message length and format: Because of the limited space on CMSs, suggestions for use are as follows: Messages should abbreviate the month in conjunction with the date. When future work will span days, the month should be noted only once in the message.
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From page 116... ...
HFG CONSTRUCTION AND WORK ZONES Version 2.0 13-10 SIGN LEGIBILITY Introduction Sign legibility refers to specific design characteristics of work zone signs that contribute to drivers' ability to perceive and understand the sign's message. A number of factors determine the legibility of work zone signs including retroreflectivity (sheeting type)
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From page 117... ...
13-11 HFG CONSTRUCTION AND WORK ZONES Version 2.0 Discussion Retroreflectivity: A report by the Virginia Transportation Council has specified that for a prismatic lens retroreflective sheeting material, the specification should include values for the material's orientation and rotation angles, in addition to its entrance and observation angles (3)
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From page 118... ...
HFG CONSTRUCTION AND WORK ZONES Version 2.0 13-12 DETERMINING WORK ZONE SPEED LIMITS Introduction Work zone speed limits refer to the reduced speed limits used in work zones to maintain safe traffic flow. Vehicle speeds in work zones are influenced by the geometrics of the roadway and the location of various work zone features such as lane closure tapers and work activity.
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From page 119... ...
13-13 HFG CONSTRUCTION AND WORK ZONES Version 2.0 Discussion Speed reductions and speed limit: Studies have found that speed limit compliance decreased when the speed limit was reduced by more than 10 mi/h. Mean speeds were approximately 5 mi/h lower within work zones with no speed limit reduction than they were upstream of the same work zones.
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