Simulation-Based Comprehensive Evaluation of Left-Turn-Waiting Zone at Signalized Intersection with Separated Left Turn Phases

This paper presents a comprehensive evaluation of a left-turn-waiting-zone (LWZ) at signalized intersections with separate left turn phases based on a simulation. Besides the normally used one-lane-left-turn-waiting-zone (OLWZ), a novel design method, multi-lane-left-turn-waiting-zone (MLWZ) was proposed. To evaluate the effectiveness of LWZ and MLWZ, this study has also conducted extensive simulation experiments. The experimental results show that various factors could influence operational efficiency of a waiting zone, including the volumes of left-turn movement, the numbers of lanes in a left-turn waiting zone, and the green time ratio of turning left traffic flow, with respect to the lane capacity, the average vehicle delay, the average number of stops, fuel consumption and emissions. Compared with LWZ, the MLWZ can improve total performance under different situations. The results of this study offer a basis for traffic practitioners, researchers, and authorities to design and assess design of MLWZ for intersections with separate left turn phases.