Effects of Speed Bumps and Humps on Motorcycle Speed Profiles

In developed countries, the use of speed humps and bumps have evolved from extensive research and testing which been properly designed and standardized. On the contrary in developing countries, no systematic and scientific studies have been carried out on that environment, especially the study on the effects that the motorcyclists response to the humps and bumps. This study therefore reveals the riders behavior when negotiating their speed to the devices. A case study was conducted in the provincial cities of Thailand where the motorcycle was a major mode of transportation. Six locations with speed humps and bumps were selected. Vehicles passing times were simultaneously recorded at 12 points along each traffic calmed link. From these data, a speed profile for each individual vehicle and for a link could be derived. It is found that speed humps and bumps have critically different impacts on motorcycle rider and passenger car driver. The smaller size speed bumps could effectively control the rider speed but have diverse impacts on the driver. These speed differences could post more safety deficiency to the site. The effect of the device on riders behavior, however, is restricted to a short spatial range (about 20-30 m before and after the device). For the speed humps, the motorcycle speeds are quite varied depending mainly on the road terrain. It is found that the motorcyclists have significant lower acceleration rate on the upgrade terrain when compared to the passenger car. Therefore, it is important to take all these rider characteristics into considerations when design the road humps to control vehicle speed in the developing countries.