Study Details

Study Title: The impacts of speed cameras on road accidents: An application of propensity score matching methods

Authors: Li et al.

Publication Date: NOV, 2013

Abstract: This paper aims to evaluate the impacts of speed limit enforcement cameras on reducing road accidents in the UK by accounting for both confounding factors and the selection of proper reference groups. The propensity score matching (PSM) method is employed to do this. A naïve before and after approach and the empirical Bayes (EB) method are compared with the PSM method. A total of 771 sites and 4787 sites for the treatment and the potential reference groups respectively are observed for a period of 9 years in England. Both the PSM and the EB methods show similar results that there are significant reductions in the number of accidents of all severities at speed camera sites. It is suggested that the propensity score can be used as the criteria for selecting the reference group in before-after control studies. Speed cameras were found to be most effective in reducing accidents up to 200 meters from camera sites and no evidence of accident migration was found.

Study Citation: Li, H., D.J.Graham, and A. Majumdar."The impacts of speed cameras on road accidents: An application of propensity score matching methods".Accident Analysis and Prevention, Vol.60,(2013)pp.148-157


CMFs Associated With This Study

Category: Advanced technology and ITS

Countermeasure: Implement automated speed enforcement cameras

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.725 27.5 4 Stars All B Not specified
0.736 26.4 4 Stars All B Not specified
0.815 18.5 4 Stars All B Not specified