Title: Safety Effectiveness of All-Red Clearance Intervals at Urban Low-Speed Intersections
Abstract: A study of the safety effectiveness of all-red clearance intervals at urban, low speed (30 mph) signalized intersections is presented. At these intersections, capacity benefits may be realized if all-red intervals are not used. Project data were collected in Minneapolis, Minnesota where engineers are considering the implementation of all-red intervals on some 104 signals that currently do not have the intervals. Results from cross-sectional and before-and-after analysis are presented along with the results of a generalized linear mixed model. Variables considered were: traffic volume, signal mounting type and presence of intersection lighting. Traffic volume was collected or estimated using several techniques developed in the study. Results indicate no safety benefit of all-red intervals for the study intersections. The report also recommends that if all-red intervals are being considered for removal at a set of intersections, those with the lowest rates of relevant crashes be considered first. Finally, the paper recommends the development of a written policy, use of ITE timing procedures, and suggests cities investigate the use of alternatives to all-red to increase signal compliance.
Publication Year: 2007
Publication Date: 2007-01-01
Language: en
Type: article
Access and Citation
Cited By Count: 5
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