A Northwestern University Transportation Center study has found that Chicago’s red-light cameras (RLC) reduce serious injury crashes at intersections with a measurable “spillover effect” on intersections without any physical cameras. The digital cameras are tied into the traffic signal system and use radar to detect vehicles approaching the intersection. The cameras record vehicles entering the intersection after the light turns red, taking still and video pictures of the rear of a vehicle, including the license plate. The report found that injury-producing crashes decreased by about 10 percent because of the camera program; more dangerous angle and/or turn crashes decreased by 19 percent. The study also found less dangerous and less frequent rear-end crashes increased by 14 percent, consistent with experience in other cities. Hani S. Mahmassani, director of the Transportation Center, led the study on the effectiveness of the program using available safety data. The team, including an expert advisory panel of traffic safety experts from across the country, conducted a rigorous analysis of existing red-light camera enforcement practices before arriving at its recommendations. Based on the analysis, the report recommends continuation of the program. "Quantitative studies conducted in this project demonstrate significant safety benefits of the current RLC program," the report concluded. The study was authorized by the Chicago City Council and commissioned by the Chicago Department of Transportation.