Red light cameras are increasingly being used in communities to deter drivers from running red lights. Numerous studies have established that red light camera en forcement sharply reduces red light violations, hut little information is available regarding crash effects. The purpose of this study was to estimate the impact of red light camera enforcement on crashes in one of the first U.S. communities to employ such cameras - Oxnard, California. Crash data from the California State-wide Integrated Traffic Records System were analysed for Oxnard and for three comparison cities that did not implement red light camera enforcement for a period of 29 months before and after implementation of the program in Oxnard. Changes in crash frequencies after enforcement were compared for Oxnard and control cities, and for signalised and nonsignalised intersections, using a generalised linear regression model. Overall, crashes at signalised intersections throughout Oxnard were reduced by 7 percent and injury crashes were reduced by 29 percent as a result of red light camera enforcement. Although the crash data did not contain sufficient detail to identify crashes that were specifically red light running events, right-angle collisions - the type of crash most associated with red light violations - were reduced by 32 percent, and right-angle crashes involving injuries were reduced by 68 percent. There was no significant effect on rear-end crashes. Because red light cameras can be a permanent component of the transportation infrastructure, crash reductions attributed to camera enforcement should be sustainable. (A)
Abstract