Impacts of Channelization Islands on the Left-turning Vehicle Maneuvers at Signalized Intersections in Japan

Abstract

The number of pedestrian injuries and fatalities involved by left-turning vehicles (in left-hand traffic) at signalized intersections occupies a very large portion in traffic accidents. Installing channelization islands, e.g. raised islands or zebra marking islands at intersections is considered as one of the most important factors influencing on conflicts between pedestrians and left-turning vehicles. However, their impacts on vehicle maneuvers have not been quantitatively analyzed. The objective of this study, therefore, is to quantitatively evaluate the impacts of channelization islands, on maneuvers of left-turning vehicles. Results of the analyses on turning vehicle maneuvers conclude that the use of raised islands gives between one-and-a-half to two times greater impacts on the trajectory and the speeds as compared to the impacts of zebra islands. The use of zebra marking islands has low influence on the vehicle trajectory and the speed.