Criteria for setting speed limits for Sri Lankan road ways

Abstract

The available knowledge and studies which have been carried out on setting speed limits for Sri Lankan road ways are very limited. Speed limit, on a given roadway, is a much important factor for road users, because that decides the travel time. This research attempts to evaluate the applicability of speed limits for Sri Lankan road network and develop a methodology for setting up speed limit for selected road section. In the selection of road sections for this research, the scope was limited to straight road sections in flat terrains in sub-urban areas and other characteristics such as shoulder conditions, roadside development and etc pretty much equal. Then, the sample speed data was collected on selected road sections according to the vehicle category. The collected data was processed and compared with existing speed limits. Besides, a questionnaire survey was carried out in order to find out drivers' knowledge and attitude about speed limits on those selected road sections. According to the obtained results, only three-wheelers and buses exceeded the speed limits which were to be adopted on the road sections by drivers. Then, the speed limit for motor cycles, car/van/jeep, light goods vehicles can be increased while Speed limit for heavy vehicles is kept as of for these road sections. After considering the results of the questionnaire survey it can be suggested that the speed limits for three-wheelers and buses can be increased by 10 kmph with respect to their prevailing speed limit values.