Impact of using indirect Left-Turns on signalized intersections’ performance

Abstract

The majority of traffic delays in urban areas occur at signalized intersections. Due to the limited availability of space and right-of-way, many transportation agencies are considering unconventional traffic control systems for intersections to improve signal efficiency and reduce overall delays. Common unconventional left-turn treatments include the right-turn followed by a U-turn (RTUT) and a U-turn followed by a right-turn (UTRT). The main goal of this study is to determine the traffic operational performance of the three left-turn treatments under different traffic conditions. The results showed that unconventional left-turn control types have less delay and travel time compared to the direct left-turn (DLT), when the U-turn locations are 200 m away from the main intersection. Also, RTUT showed superior performance over the other left-turn control types, when the U-turn locations are 100 m away from the main intersection.