信控交叉口借道左转设计的延误优化研究

Delay optimization of the contraflow left-turn lane design at signalized intersection

为准确分析交叉口借道左转设计的左转延误,针对现有的延误模型的不足,建立一个合适的延误优化模型,并提升其设置的科学性。先对逆向车道长度进行优化;再通过分析左转车辆的累计到达驶离曲线,以左转总延误最小为优化目标,建立一种新的考虑预信号延误的优化模型;最后,以长沙市芙蓉中路一个交叉口为实例,进行验证,分析左转到达流率对借道左转设计延误的影响及逆向车道长度对左转车均延误的影响。研究结果表明:左转流率越大,越能充分发挥借道左转设计的优势,该模型的左转延误下降可达59.21%;当左转流量偏低时,预信号位置的延误占比较大,随着左转流量的增大,传统车道和逆向车道的延误占比逐步增加。该研究可以准确评价借道左转设计的实用性和优劣程度,对借道左转设计的推广与应用具有重要意义。

In order to accurately analyze the left-turn delay of the borrowed left-turn design at intersections,a suitable delay optimization model is established to address the inadequacies of the existing delay models and to improve the scientificity of their settings.Firstly,the length of the reverse lane is optimized.Then,by analyzing the cumulative arrival/departure curves of the left-turning vehicles,a new optimization model considering the pre-signal delay is established with the objective of minimizing the total left-turning delay.Finally,a validation is carried out at an intersection on Furong Road in Changsha City,which analyzes the effect of the left-turn arrival rate on the delay of the borrowed-left-turn design as well as the effect of the length of the reverse lane on the delay of the leftturning vehicles.The results of the study show that:the larger the left-turn flow rate is,the more the advantage of the borrowed left-turn design can be fully utilized,and the left-turn delay can be reduced up to 59.21%;when the left-turn flow rate is low,the delay of the pre-signal position accounts for a larger proportion,and with the increase of the left-turn flow rate,the delays of the traditional and reverse lanes account for a gradual increase in the delay proportion.This study can accurately evaluate the practicality and advantages of the borrowed left-turn design,which is of great significance for the further promotion and application of the borrowed left-turn design.