Human Factors Guidelines for Road Systems: Second Edition (2012) / Chapter Skim
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Pages 120-132
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Task Analysis of Rail-Highway Grade Crossings .
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T AS K A NA LY SI S OF R AI L -H IG HW AY G RA DE C RO SSI NG S In tr od uc ti on This guideline addresses the key factors found to affect driver decisions regarding whether to obey traffic control devices at rail-highway grade crossings. Most crossings have traffic control devices (TCDs)
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Discussion Many of the driver factors that are incorporated into this guideline are covered in more detail in subsequent guidelines. It is important to consider these factors when planning a crossing because ultimately drivers decide whether they will comply with a warning device.
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D RIVER I NFORMATION N EEDS AT P ASSIVE R AIL - H IGHWAY G RADE C ROSSINGS Introduction This guideline refers to the information that drivers need to behave safely at rail - highway grade crossings that are protected by passive devices. This is especially relevant for crossings with only passive protection since drivers carry the full responsibility of determining if a train is approaching.
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Di scu ssi on The inform ation needs described in the guideline on the previous page are not adequately addressed by crossbuck warning devices alone. The signs and plaques provided are examples of countermeasures that can be used to fill som e of these needs.
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TIMING OF ACTIVE TRAFFIC CONTROL DEVICES AT RAIL-HIGHWAY GRADE CROSSINGS Introduction This guideline refers to the warning time, or the time between the initiation of the flashing light traffic control devices and the arrival of the train. If the total warning time or portions of the timing are too short, drivers are at a risk of not being able either to stop in time for the gates to descend or to pass over the crossing from the dilemma zone.
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Di scu ssi on Warning times: Richards and Heathington ( 1 ) conducted field observations and a laboratory study to deter mi ne the expectations of drivers for warning ti me s at rail-highway grade crossings.
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FOUR-QUADRANT GATE TIMING AT RAIL-HIGHWAY GRADE CROSSINGS Introduction This guideline refers to the gate interval time, which is the length of time between the initiation of the descent of the entry gate and the initiation of the descent of the exit gate at a crossing with a four-quadrant gate device (1)
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Di scu ssi on Four-quadrant gates are desirable for their ability to restrict through traffic at grade crossings. Four-quadrant gates are more effective at controlling gate-rushing, that is passi ng around gate arm s that are already descended on two - quadrant gates (see "Countermeasures to Reduce Gate-Rushing at Crossings with Two-Quadrant Gates" on page 14-10)
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COUNTERMEASURES TO R ED UC E GATE -R US HI NG AT CROSS IN GS WI TH T WO -Q UA DR AN T G AT ES In tr od uc ti on Gate-rushi ng is a type of violation that occurs when drivers drive under gate arm s as they are descending or around gate arm s that are already in the lowered position. Although gates are so me of the mo st restrictive crossing control devices, 9.1 crashes per 1 mil lion trains are still occurring at crossings with two-quadrant gates ( 1 )
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From page 130... ...
Discussion Centerline barriers: The two unsafe behaviors that were examined with centerline barriers were gate-rushing and driver U-turns while waiting for trains to pass through the crossing. When tested at two sites, centerline barriers reduced gate-rushing by 35% on average and U-turns at gates by 82% on average (2)
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HUMAN FACTORS CONSIDERATIONS IN TRAFFIC CONTROL DEVICE SELECTION AT RAIL-HIGHWAY GRADE CROSSINGS In tr od uc ti on This guideline refers to the human factors that apply to three different levels of control at rail-highway grade crossings: Yield signs, Stop signs, and automatic gates.
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From page 132... ...
Discussion Compliance issues are not addressed in this discussion since they are covered in "Task Analysis of Rail-Highway Grade Crossings" on page 14-2 as well as the design issues section below. Exact guidance regarding when to install each control device can be found in the Highway/Rail Grade Crossing Technical Working Group document (3)
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