信号控制交叉口群左转交通协调设计方法

研究了拥挤交叉口和非拥挤交叉口构成的交叉口群左转交通组合协调设计方法.首先对比分析了允许左转和禁止左转交通对交叉口最优信号周期、车均延误和饱和度的影响.然后分析了禁左后左转交通流的可替代路径,重点分析了利用交叉口群内次要交叉口形成U-turn完成左转的情形,研究了交叉口群左转相位的协调设计方法和相应的空间协调设计方法.基于此,以交叉口群总延误最小为目标提出了交叉口群左转相位组合优化模型,在模型中还考虑了公交车流为直行的条件下,禁止拥挤交叉口左转车流带来的公交优先效益.最后应用一个有两个交叉口且有路中型公交专用道的实际路网,采用车均延误和饱和度为指标对比分析了两个交叉口均允许左转和按照本文方法协调设计完成左转两种情形.案例分析表明,相邻交叉口左转交通的协调设计不但能够改善交叉口机动车的服务水平,而且能够显著降低直行公交车辆的延误,同时,该协调设计方法对整个系统的负面影响较小.

Coordination Design of Left Movements of Signalized Intersections Group

A study is made of the coordination design method of left turn movements for intersections group which is composed of high loaded intersections and light loaded intersections.Firstly,an analysis is made of the effects of prohibiting left turn movements on optimal cycle length and average delay.Secondly,alternative routes,especially U-turn,for left turn movements that are prohibited at high loaded intersection are proposed and compared at hypothetic grid road network.Thirdly,the coordination design method of left turn phase for intersection-group is put forward,and the efficiency of straight bus movements is also considered in the model.A field intersection-group of the Beiyuan Road of Ji'nan city,where bus exclusive lane is located in median,is applied to testing the above proposed method.A high-performance microscopic traffic simulation program,VISSIM,is adopted to evaluate the Coordination Design of Left Turn Phase concept.The results show that the method can reduce delay of buses and motor traffic with only a slight adverse effect on the system.