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The contents of this report reflect the views of the author(s), who is responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Virginia Department of Transportation, the Commonwealth Transportation Board, or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. Any inclusion of manufacturer names, trade names, or trademarks is for identification purposes only and is not to be considered an endorsement.


Safety Benefits and Best Practices for Intersection Lighting
Yingfeng (Eric) Li, Ph.D., P.E., Rajaram Bhagavathula, Ph.D., Travis N. Terry, Ronald B. Gibbons, Ph.D., and Alejandra Medina
Year: 2019
VTRC No.: 20-R31

Nighttime safety continues to be a major concern for transportation agencies across the country. Roadway lighting has been widely used as a countermeasure for nighttime crashes. However, safety engineers and researchers frequently lack effective tools when determining exactly how lighting should be optimized to maximize safety while conserving energy. This project involved an extensive effort to investigate traffic safety lighting impacts at intersections. Based on the results, the project identified optimal lighting levels for different types of intersections and developed guidelines to facilitate lighting needs analysis and design at the Virginia Department of Transportation. During this study, a crash analysis showed a 2.9% reduction in night-to-day crash ratio for each 1-lux increase of minimum illuminance at intersection boxes. Additionally, the project team found a benefit-cost ratio between 2.6 and 5.6 for unsignalized intersections and between 2.8 and 7.9 for signalized intersections, assuming one injury nighttime crash per year at such locations and depending on whether existing poles can be used.