Evaluation of blue confirmation lights at signalized intersections in Overland Park, Kansas, to reduce red light running violations.

Lindheimer, Tomás E.; Fitzsimmons, Eric J.; Schrock, Steven D.; Boakye, Kwaku · 2015 · ROSA P / Kansas. Dept. of Transportation. Bureau of Research

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Summary

This study evaluates the effectiveness of blue confirmation lights as a low-cost countermeasure to reduce red light running (RLR) violations at signalized intersections. Motivated by the significant safety and economic impacts of RLR—cited as a cause of 676 fatalities in 2009—and the legal prohibition of automated enforcement cameras in Kansas, the research aimed to determine if confirmation lights, which aid police enforcement by illuminating downstream when a vehicle runs a red light, could deter violations. The study also sought to identify other factors contributing to RLR behavior. The research was conducted in Overland Park, Kansas, between September 2012 and March 2014. Blue confirmation lights were installed at two treatment intersections. To assess impact, traffic video was recorded at these treatment sites, nearby "spillover" intersections, and control sites without the lights. Data collection occurred during morning (7 a.m. to 9 a.m.) and afternoon (4 p.m. to 6 p.m.) peak hours, totaling 583 hours of video across 14 intersections. Observations were made before deployment, one month after, and three months after installation. The methodology included a test of proportions to compare violation rates and a negative binomial regression model to analyze significant factors influencing RLR. Additionally, a "time into red" analysis measured how long after the signal turned red vehicles entered the intersection. The results indicated that blue confirmation lights did not significantly reduce RLR violations. Statistical tests of proportions showed no significant decrease in violations at treatment sites. In fact, a global increase in RLR violations was observed after deployment, suggesting external factors influenced the rise rather than the lights themselves. The "time into red" analysis revealed that the majority of violations occurred within one second of the red signal onset. The negative binomial regression model confirmed that the presence of confirmation lights was not a significant predictor of RLR violations. Instead, the model identified lane volume, the presence of a right-turn lane, and traffic movement type (left-turn vs. through movement) as significant factors affecting violation rates. The study concludes that blue confirmation lights are not an effective standalone countermeasure for reducing red light running violations in this context. While they offer a low-cost method to assist enforcement, they do not deter driver behavior. The findings suggest that RLR is more strongly influenced by traffic operational characteristics, such as volume and lane configuration, than by the presence of confirmation lights. This implies that communities seeking to mitigate RLR may need to rely on other engineering or enforcement strategies, as confirmation lights alone do not provide the safety benefits anticipated.

Key finding

Blue confirmation lights did not significantly reduce red light running violations, and a negative binomial regression model confirmed they were not a significant factor in the observed violations.

Methodology

on_road

Sample size: 14

Provenance

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Summary generated by qwen3.6-27b-prismaquant on 2026-06-10; verification: verified.

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• roadway lighting effects