Evaluating the Speed Reduction Effectiveness of Speed Bump on Local Streets

The effects of speed bump on reducing vehicle speeds are still unclear though they have been extensively used on local streets in China. The primary objective of this paper is to evaluate the impacts of speed bump on speed reduction on local streets. The research team measured 3,000 vehicle speed observations at 15 locations around speed bumps on local streets in Nanjing area in China. The results of t-tests show that the vehicle speeds at the speed bump were significantly lower than those at upstream and downstream control locations at the treated sites. The reductions in mean speed were 6.7 km/h and 7.0 km/h in two treatment sites, and the reductions in the 85th percentile speed were 5.0 km/h and 8.7 km/h. The influence area of speed bump is generally less than 120 m.