Investigating the Effectiveness of Traffic Calming Strategies on Driver Behavior, Traffic Flow and Speed

This report highlights the findings of a project to determine the impact of traffic calming strategies on driver behavior, traffic flow, and speed. Researchers used a number of different approaches, including a literature search to determine results at a national level and local before-and-after studies in areas that implemented new traffic calming strategies. Researchers also compared an actual street before and after implementation of traffic calming devices to a driver simulation study of a street with and without traffic calming devices. Research results indicate that traffic calming can have a limited impact on average driver speed. The greatest impacts on speed often occur in reducing the number and speed of outliers, or those who travel at speeds greater than the 85th percentile speed. The report details the impact of different types of traffic calming strategies on traffic speed and volume.