Traffic Circles – Impact on motor vehicle, cyclist-MV, pedestrian-MV crashes with injuries

摘要

Local street intersections with traffic circles have been found to pose a higher injury risk to cycliststhan intersections with stop sign control. An outstanding question is the effect of traffic circles oninjuries to people walking and driving. We examined this issue using an Insurance Corporation ofBC dataset of 40,626 crashes that occurred at local street intersections in Vancouver from 1996to 2013 to determine whether traffic circles were associated with injury risk for three types ofcrashes: motor vehicle (MV); cyclist-MV; and pedestrian-MV. Relative risks were calculated usingthree comparisons: with vs. without traffic circles; traffic circles vs. intersections within one block(“matched”); and after vs. before traffic circles. For motor vehicle crashes, traffic circles hadrelative risks of 0.17 to 0.53, resulting in 11 to 46 fewer injuries per year in Vancouver, a city withabout 200 traffic circles. For cyclist-MV crashes, traffic circles had relative risks of 2.4 to 4.6,resulting in 10 to 12 more injuries per year. For pedestrian-MV crashes, traffic circles had relativerisks of 0.97 to 1.9, resulting in 0 to 2 more injuries per year. These results suggest that trafficcircles should not be used as a traffic calming measure along local street bike routes. Saferalternatives (i.e., raised crossings, traffic diversion) should be tried to determine if they are betterfor all modes of travel.