Research Papers (2009 – 2013)

Abstract

Intersection Safety Devices (ISDs) are used at signalized intersections for both red-light running and speeding enforcement. These devices use cameras to photograph offending vehicles and tickets are later issued. With regards to identifying candidate locations for ISDs, red-light running enforcement principally targets angle or left-turn-opposed type crashes, caused by a vehicle proceeding through the intersection after the onset of red. Intersection speed enforcement targets any type of crash which involves one or more speeding vehicles. To maximize safety benefits, the installation of ISDs should target signalized intersections with evidence of a high frequency of red-light-running or speeding related crashes. Because speeding is unreliably reported as a crash cause, the identification of suitable intersections for automated speed enforcement needs to consider all crash types. This paper describes the development of a methodology for identifying candidate intersection approaches for ISDs. Signalized intersection inventory, traffic volume and crash data were obtained for signalized intersections in the City of Edmonton and Safety Performance Functions (SPFs) for estimating the expected crash frequencies of target crashes were developed to support the methodology. The methodology considers the empirical Bayes estimates of expected red-light-running related crashes and all crashes on enforced through-lanes separately, producing a ranking measure for each intersection approach for each crash type. A combined ranking measure for each approach is then determined by combining these ranks.

Craig Lyon, Bhagwant Persaud, Yongsheng Cheng