随机条件下单点交叉口绿灯时间计算方法研究

Calculation Method of Green Time for Pre-timed Signal Control at Isolated Intersection under Random Condition

通过分析交叉口交通流的随机特性,建立了以期望排队长为目标函数的绿灯时间优化模型。在模型求解过程中,利用Lagrange乘数法给出了求解随机期望值模型的解析算法,通过随机仿真逼近随机函数得到了交叉口各相位绿灯时间的最优值。最后以两相位信号交叉口为例进行了算例试验和分析,结果表明到达率的随机变化特性对于绿灯时间的分配有明显影响,仿真结果验证了模型和算法的正确性。

By analyzing the stochastic characteristics of traffic flow at intersection, a green time optimization model for pre-timed signal at isolated intersection, which uses the expected queue length as its optimization objective, was established. In the process of solving, the analytical algorithm for solving the model was presented by the l.agrange multiplier method on the basis of the stochastic function which was approached by the random simulation. By using this method, the optimal value of the phase green time of the intersection was obtained.At last, a simulation example of a two-phase signalized intersection was presented. The result shows that the random variation of arrival rate has an obvious effect on allocating the green time, which illustrates the correctness of the model and the algorithm.