Impact of Road Lane Narrowing Traffic Calming Treatments on Speed and Volume

The purpose of this paper is to present a study on the effects of colored slurry seal traffic calming treatment in slowing down speeds and reducing traffic volume on residential streets. The study presented is a before-and-after study that not only considered changes on the treated road but also examined changes that were taking place in the overall behavior of traffic. The before data consisted of volume and speed of traffic prior to the application of the slurry seal and the after data were collected from the same sites one month and then four months after the seal was installed. The results of this analysis revealed a reduction in vehicle speeds from before to one month and four months after periods. But the results of the study on traffic volume were inconclusive. The 24 hour average traffic volume one month after implementation of the traffic calming showed a statistically significant increase. It is speculated that a possible reason for this increase might be the novelty effect of the new traffic calming treatment measure, attracting drivers to the treated site to view the treatment. However, four months after application of the slurry was introduced the average 24 hour traffic volume showed a statistically significant decrease from the before period.