Red Light Running in Iowa Automated Enforcement Program Evaluation with Bayesian Analysis

Red light running (RLR) is a serious safety issue that results in more than 100,000 crashes and 1,000 fatalities annually. In Iowa, RLR accounts for 21% of total crashes at signalized intersections and 35% of fatal and major-injury crashes at signalized intersections, according to data analyzed from 2001 to 2006. As transportation agencies struggle to address RLR, they turn increasingly to the use of red light camera enforcement. In Iowa, three communities currently use RLR camera enforcement. One of the communities, Davenport, installed cameras in 2004; 2 years of crash data after installation were available for analysis. A Bayesian statistical before-and-after analysis was used to evaluate the effectiveness of Davenport's RLR cameras. The analysis included control intersections. The results of the analysis indicated that the cameras were effective in reducing total crashes and RLR crashes. Results also indicated that rear-end crashes related to RLR did not increase at camera-enforced intersections.