Effect of Red Light Cameras on Accident Risk at Intersections

Abstract

One major cause of accidents at signalized intersections is vehicles running red lights. To discourage red light running (RLR), a number of authorities have installed red light camera (RLC) systems on the approaches to these signalized intersections. There have been indications from several studies that RLCs have been effective in curbing RLR; this leads to potential reduction in right-angle collisions. However, there are also concerns over a possible increase in rear-end collisions. This paper investigates the effect of RLCs on accident risks at signalized intersections for both right-angle collisions and rear-end collisions. A binary logit model was preliminarily developed to examine how the stopping–crossing decision of drivers at the onset of amber is affected by geometric, traffic, and situational variables. Results showed that the presence of RLCs is one of the five significant factors affecting a driver's decision to cross at the onset of amber. A multinomial logit model further confirmed that RLCs are effective in reducing RLR frequency. Further analysis on the fitted models revealed that while the presence of RLCs is effective in reducing risk of right-angle collisions, it has a mixed effect on the risk of rear-end collisions. Whether the RLC reduces or increases the possibility of rear-end collisions depends on the speed of the trailing vehicle and the headway between vehicles.