Value of Confirmation Lights and Their Unintended Impact on Driver Compliance and Deterrence to Running a Red Light

In the United States, red light running (RLR) continues to be a safety concern for many communities with signalized intersections. In 2012, the Insurance Institute for Highway Safety reported that nationwide, RLR had resulted in 683 fatalities and 133,000 injury-related crashes. Confirmation lights have been deployed in many communities as a countermeasure to aid law enforcement in reducing RLR violations; however, the effectiveness of confirmation lights has not been well documented. This research study was conducted to determine the effectiveness of confirmation lights at signalized intersections for the purpose of reducing RLR violations. Confirmation lights were installed for the protected left-turn movements at two signalized intersections in Lawrence, Kansas. In addition to the two treatment sites, 11 comparison sites, including six spillover intersections and five control intersections, were studied. A before–after analysis was conducted with field-based violation data. Without changing the local, traditional police department–run RLR enforcement program during the study period, video data were collected before installation, and 1 month and 3 months after installation. A test of proportions found a statistically significant 42% reduction in left-turning RLR violations 3 months after the installation of confirmation lights at the treatment sites. An analysis of RLR time into red with chi-square tests indicated that the system was less effective in changing the time from the onset of red until the mean RLR violation occurred. Overall, the presence of the confirmation lights at the signalized intersection indicated effectiveness in both reducing the number of RLR violations and also changing driver behavior.