Effectiveness and Site Selection Criteria for Red Light Camera Systems

The objective of this paper is to evaluate the safety effectiveness of automated traffic enforcement systems, that is, red light cameras, installed at 254 signalized intersections in 32 jurisdictions in Texas. In addition, criteria for site selection were evaluated to provide analytical resources for camera installation. A before–after study by the empirical Bayesian methodology was performed to remove the regression-to-mean bias during the evaluation of treatments. The results indicate significant decreases in the incidences of all types of red light running (RLR) crashes and right-angle RLR crashes by 20% and 24%, respectively. A significant increase of 37% for rear-end RLR crashes was discovered. The study results suggest that a significant safety benefit for red light cameras is achieved if intersections have four or more RLR crashes per year or have two or more RLR crashes per 10,000 vehicles. Red light cameras show counterproductive results if intersections experience fewer than two RLR crashes per year or have one crash per 10,000 vehicles per year.