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Citation |
Taylor DB. Transp. Res. Rec. 1993; 1405: 13-20. |
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Copyright |
(Copyright © 1993, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing) |
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DOI |
unavailable |
PMID |
unavailable |
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Abstract |
Clearance intervals (including both the yellow change and all-red clearance intervals) at signalized intersections that are of inadequate lengths for bicycle/rider units may cause accidents. Steps that can be taken to provide safe clearance intervals for bicycles and automobiles are examined. Data on bicycle/rider unit speed, acceleration, and deceleration were collected and analyzed. Using the results of the analysis and an accepted theory for computing safe clearance intervals, a methodology is obtained for computing safe clearance intervals for traffic containing bicycles and automobiles. The clearance interval required by bicycles will probably be somewhat larger than that for automobiles. Providing a single longer clearance interval for both users may cause undue delay or unsafe conditions for automobiles. Therefore, alternatives that provide different warning signals to each user at the appropriate time are presented, and the question of whether this particular signal should be timed for bicycles is answered. A mathematical expression is derived for computing the probability of a bicyclist's being caught in the intersection when the cross-street traffic receives a green. This probability allows one to compute the number of bicycles per hour that will be caught in the intersection. Since traffic engineers require information of this nature to provide safe intersection clearance for both automobiles and bicycles, it is hoped that this and subsequent work will provide methodologies necessary to incorporate into common design manuals, such as AASHTO's "Guide for the Development of Bicycle Facilities" and various state and city manuals. Language: en |
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Keywords |
Acceleration; Accident prevention; Automobiles; Highway accidents; Intersections; Mathematical models; Speed; Traffic signals; Bicycles; Highway traffic control; Deceleration; Decision theory; Probability |