The safety consequences of running red lights are considerable. A study of urban crashes reported that running red lights and other traffic controls was the most common type of crash (22 percent). Although red light camera enforcement is controversial, the number of communities with red light camera programs continues to increase, from 0 communities in 1992, to 25 in 2000 and 501 in 2010. The body of research on red light camera enforcement has shown that camera enforcement in general reduces the number of red light running violations at treated intersections as well as at non-treated intersections (due to the "spillover" effect). Research has also found that communities realized a safety benefit of lower numbers of intersection crashes after having installed red light cameras. The current study extends this research by examining the effects of red light camera enforcement on per capita fatal crash rates at signalized intersections.
A before-after analysis of the relationship between red light camera enforcement programs on per capita fatal crash rates at signalized intersections examined data from 14 large cities (defined as having a population of 200,000 or more) in the United States. These cities had red light enforcement programs from 2004-08 but not from 1992-96. These cities were also compared to similar cities that did not have camera enforcement in either period. The analysis used Poisson regression to determine per capita fatality rates as a function of the presence of a red light enforcement program, land area, and population density.
Overall, there was a decline in fatal red light running crashes in cities with and in cities without enforcement programs. However, the cities with red light camera enforcement programs had a larger decline than those without camera enforcement (35 versus 14 percent).
Cities with camera enforcement had a 24 percent lower rate of fatal red light running crashes during 2004-08 relative to what it would have been without camera enforcement. Further, the rate of all fatal crashes at signalized intersections in cities with enforcement programs was 17 percent lower than what it would have been without camera enforcement.
These results demonstrate that red light camera enforcement programs produce significant safety benefits by not only reducing fatal crashes from red light running but also by reducing the number of fatal crashes of all types at signalized intersections.