At head of title: National Cooperative Highway Research Program.

Red light running is a significant public health concern, killing more than 800 people and injuring 200,000 in the United States per year (Retting et al., 1999a; Retting and Kyrychenko, 2002). To reduce red light running in Virginia, six jurisdictions (Alexandria, Arlington, Fairfax City, Fairfax County, Falls Church, Vienna) deployed red light cameras at some point during the 10-year period when they were permitted under Virginia law. This report documents the safety impacts of those cameras based on 7 years of crash data for the period January 1, 1998, through December 31, 2004. Consistent with the findings of a previous Virginia study (Garber et al., 2005), this study finds that cameras are associated with an increase in rear-end crashes (about 27% or 42% depending on the statistical method used as shown in Tables ES1 and H1) and a decrease in red light running crashes (about 8% or 42% depending on the statistical method used as shown in Tables ES1 and H2). This report also shows that there is significant variation by intersection and by jurisdiction: one jurisdiction (Arlington) suggests that cameras are associated with an increase in all six crash types that were explicitly studied (rear-end, angle, red light running, injury red light running, total injury, and total) whereas two other jurisdictions saw decreases in most of these crash types. It is therefore not surprising that when the comprehensive crash costs for rear-end and angle crashes are monetized, the cameras are associated with an increase in crash costs in some jurisdictions (e.g., an annual increase of $140,883 in Arlington) and a net reduction in comprehensive crash costs in other jurisdictions (e.g., an annual reduction of $92,367 in Vienna). When these results are aggregated across all six jurisdictions, the cameras are associated with a net increase in comprehensive crash costs. However, when considering only injury crashes, if the three fatal angle crashes that occurred during the after period are removed from the analysis (the only fatalities that occurred during the study out of 1,168 injury crashes), then the cameras were associated with a modest reduction in the comprehensive crash cost for injury crashes only. These results cannot be used to justify the widespread installation of cameras because they are not universally effective. These results also cannot be used to justify the abolition of cameras, as they have had a positive impact at some intersections and in some jurisdictions. The report recommends, therefore, that the decision to install a red light camera be made on an intersection-by-intersection basis. In addition, it is recommended that a carefully controlled experiment be conducted to examine further the impact of red light programs on safety and to determine how an increase in rear-end crashes can be avoided at specific intersections.

Red Light Cameras (RLCs) have been used in a number of U.S. cities to yield a demonstrable reduction in red light violations; however, evaluating their impact on safety (crashes) has been relatively more difficult. Accurately estimating the safety impacts of RLCs is challenging for several reasons. First, many safety related factors are uncontrolled and/or confounded during the periods of observation. Second, "spillover" effects caused by drivers reacting to non-RLC-equipped intersections and approaches can make the selection of comparison sites difficult. Third, sites selected for RLC installation may not be randomly selected, and as a result may suffer from the regression to the mean effect. Finally, crash severity needs to be considered to fully understand the safety impacts of RLCs. With these challenges in mind this study was designed to estimate the safety impacts of RLCs on traffic crashes at signalized intersections in the state of Arizona and to identify which factors are associated with successful installations. RLC equipped intersections in the cities of Phoenix and Scottsdale are examined in detail to draw conclusions as to the relative success of RLC programs in these two jurisdictions. Both jurisdictions are operating successful installations of RLCs. Factors related to RLC effectiveness appear to include crash type and severity, left-turn phasing, presence of warning signs, approach speeds, and signal timing. Recommendations are made as to under what conditions should RLCs be considered.

The objectives of this research project are to: (1) quantify the safety impact of red-light-running at intersections in Texas, and (2) provide guidelines for identifying truly problem intersections and whether enforcement or engineering countermeasures are appropriate. This report documents the findings from the first year of a two-year project. During the first year, data were collected to quantify the character and extent of red-light violations and related crashes in Texas. Data were also collected to quantify the effectiveness of intersection traffic control enforcement. The findings from a review of the literature on red-light-running and an analysis of red-light-running crash data are included in this report. A procedure for identifying and quantifying red-light-running-related crashes is described.