Evaluating the Use of Red Light Running Photographic Enforcement Using Collisions and Red Light Running Violations

The issue of red light running (RLR) has long been a problem throughout the United States. There is considerable debate within the general public and public agencies regarding the use of photographic enforcement to deter red light violations. Many studies have been conducted on the effectiveness of red light cameras (RLCs) at reducing collisions. However, the question still remains as to whether RLCs actually change driver behavior. The need for more thorough study motivated this research effort to help define the effectiveness of RLCs within the City of Raleigh, North Carolina. Four specific tasks were identified to help in this research effort. First, a literature review was conducted. Many studies indicate that RLC enforcement reduces the frequency of collisions at treated intersections. However, there are a limited number of rigorous studies (especially those in the United States and in North Carolina). Six focus groups were convened in an effort to gather information on attitudes, opinions, and beliefs associated with photographic enforcement to better enhance traffic law enforcement. Two community and four professional focus groups were assembled. Overall, the perception of photographic enforcement was positive. The majority of participants agreed that the presence of RLCs would make them more aware of individual driver behavior; however, most of the groups agreed that the range of driver education varied widely and that driver education should be a priority. In an effort to analyze the effect of RLCs on driver behavior, two types of analyses were completed. The first type of analysis was a before-after collision study. The following three types of improved before-after collision studies were used: accounting for causal factors, a comparison group analysis, and an improved comparison group analysis accounting for the halo-effect. Each of these studies analyzed four categories of collisions including total, red light running related, angle, and rear end. Based on the comparison group study, collisions were effectively reduced by 17%, 22%, 42% and 25%, respectively. In addition to the analysis of collisions, red light running violations were analyzed to see if there was a change in driver behavior related to dangerous violation times (violations considered to possibly cause collisions) greater than two seconds. Using the Chi-Square Test of Independence, the frequency of unsafe red light running violations reduced significantly with a p-value less than 0.001. Based on these findings, RLCs appear to have a positive effect on driver behavior. Focus groups indicate that overall there is a positive perception of RLCs as a countermeasure to deter red light running. Based on the comparison group collision study, all collision group types decreased considerably. Lastly, red light running violations related to dangerous red light violation times dramatically decreased, providing further justification for the use of RLCs as a red light running countermeasure.