考虑主路左转延误的主路优先交叉口信号设置流量阈值

为了进一步完善主路优先交叉口信号灯设置流量条件,考虑了主路左转车流延误对交叉口信号灯设置条件的影响.通过分析主路左转车流在信号灯设置前后的交通特性,利用控制延误方法和Webster方法的研究思路,分别建立主路左转车流在信号灯设置前后的车均延误改进模型.从交叉口交通运行效率的角度出发,以交叉口车均延误作为判别指标,建立信号灯设置前后交叉口等车均延误曲线,以此曲线作为判断交叉口是否需要设置信号灯的阈值条件,同时还给出了不同主路左转车流比例下的流量阈值.与美国MUTCD提出的阈值曲线相比,考虑左转车流延误影响的流量阈值曲线更符合我国主路优先交叉口交通特性,具有更强的实用性.

Signal setting critical volume for two-way stop-controlled intersection based on major left-turn delay

In order to improve the signal setting warrant of two-way stop-controlled(TWSC) intersections,the impact of major left-turn delay on signal setting critical volume for TWSC intersections is considered.After analyzing the characteristics of major left-turn flow,the control delay method and the Webster method are used to develop major left-turn flow’s average vehicle delay models before and after signal control setting,respectively.Based on traffic efficiency,vehicle average delay is regarded as the discrimination index,and the curve of vehicle average delay is given as the critical volume for determining whether the intersection needs to be set signal.Besides,critical volume curves of different left-turn flow rates are given.Compared with the curve offered by Manual on Uniform Traffic Control Devices,U.S.,the critical volume curve considering major left-turn delay can fit the traffic characteristics of Chinese intersections well,therefore,it is more practical for Chinese TWSC intersections.