In the 2004-2007 period, the Mission Street SE and 25th Street SE intersection in Salem, Oregon showed relatively few crashes attributable to red light running (RLR) but, since a high number of RLR violations were observed, the intersection was identified as having a high crash potential. ODOT approved the installation of RLR cameras for a trial period to study the results of RLR cameras. Cameras were installed in February 2008 in the westbound and northbound directions. A before and after study of the crashes involving westbound and northbound drivers at the Mission and 25th intersection was completed. In the 50 months prior to the camera installation crashes averaged 0.62 per month. In the 21 months after installation, the average increased by 77.4% to 1.10 per month. Crash cost estimates for different types of crashes make it possible to account for the expectation that RLR cameras are likely to result in fewer angle crashes, which are often severe, and more rear end crashes, for which injuries tend to be less severe. The estimated average monthly crash costs increased from $16,296 before the cameras were installed to $27,738 after the cameras were installed. Crashes increased only slightly or not at all at two comparison intersections, whereas the crashes increased substantially at the Mission at 25th intersection. Since traffic volumes declined slightly from the pre- to post-installation periods, the crash data were not normalized. After camera installation, violations decreased by 43 percent in the westbound direction and 23 percent in the northbound direction. At both the westbound and northbound approaches, left turning vehicles accounted for the overwhelming majority of the violations. (Author/publisher)
Samenvatting