Modeling and Simulation on Left-turn Waiting Area at Isolated Signalized Intersection

Left-turn waiting area can improve the capacity and operational efficiency of the isolated signalized intersection. Based on the former researches and survey data, in this paper, we model the left-turn waiting area by dint of stop lines A, B and its length I-AB, and parameters of left-turn signal, t(1), t(2), t(3), t(3). According to the flow chart and taking advantage of simulation software VISSIM, we emulate 2 scenarios about setting left-turn waiting area or not and just evaluate the left-turn flow at each approach. The results indicate that, comparing to the no waiting area scenario, the travel time of I.H-H with 3 signal phases is reduced by 5.64%, and average queue lengths of its 2 approaches are cut by 14.55% and 15.11%. The delay of I.W-W with 4 signal phases is declines by 5.64%, while the volume is increased by 7.01%. However, the results also show that the stop rates added 0.73 and 0.64 respectively.