Investigating speed patterns and estimating speed on traffic-calmed streets

Previous research has shown that speed reduction on residential streets can be attained through traffic calming. This research examines the speed profiles of individual vehicles on traffic-calmed streets, in order to provide a better understanding of how drivers react to calming devices over an extended street length and to find ways of estimating speeds along traffic-calmed streets. Results indicate that traffic-calmed streets do not necessarily promote low speed environments. It was found that 85th percentile speeds at long distances from calming devices were 45-55 km/h for horizontally deflected streets and 40-45km/h for vertically deflected streets. The speed hump and the angled slow point produced the biggest speed reductions, with the 2-way mid-block narrowings causing no significant speed changes. Smaller variations in speeds were recorded on the speed hump and the raised angled slow point, while the speed table registered a higher variation. This suggests that drivers have different perceptions of appropriate operating speeds. For multiple devices, larger spacing produced higher speeds between devices. These findings, along with speed difference curves and speed-spacing models developed from this research, can aid in the selection of device type and spacing between devices in order to improve the effectiveness of traffic calming.