The effectiveness of red light cameras in the United States-a literature review.

ABSTRACT

OBJECTIVE: To examine the available scientific evidence based on peer-reviewed publications concerning the effectiveness of red light cameras (RLCs) within the U.S. traffic system. METHODS: Relevant literature published prior to December 2012 was retrieved from the PubMed, Medline, and Engineering Index databases using free-text term queries. Jurisdictions with either a fixed number of RLCs studied or area wide programs within the United States were included. RLC studies with additional interventions were excluded. Nine RLC studies were extracted and grouped into 3 categories based on outcome measures: violations, crashes, and injuries/fatalities. RESULTS: All 9 studies reviewed showed significant reductions in the frequency/rate of violations, crashes, and injuries at intersections after RLC implementation. RLC interventions appear to decrease violations, crashes, and injuries at intersections. CONCLUSIONS: Despite limited peer-reviewed publications available in the literature, it appears that RLCs decrease violations, crashes, and injuries at intersections. Some studies, however, contained methodological shortcomings. Therefore, the apparent effectiveness should be confirmed with stronger methodological approaches. Although spillover effects appeared to be evident, many of the jurisdictions examined were small in area. Thus, it is unknown whether spillover resulting from RLCs would have similar effects in large metropolitan areas. To determine the full public health impact of RLC programs, crashes, injuries, and fatalities should be considered as primary outcomes of interest. To accomplish this requires a clear definition of which types of crashes will be included for RLC studies. Lastly, it is unknown whether RLCs would be effective in reducing crashes resulting from distracted or alcohol-impaired drivers. Future studies should examine the effects of RLCs by exclusively analyzing these crash types.