考虑关键路径序列的干道绿波协调控制方法

传统的干道协调控制通常以协调流向的通行效率最大为优化目标, 然而在实际交通流量波动环境中, 某些非协调流向的流量在局部时段可能与协调流向相当甚至高于协调流向, 从而影响干道运行的总体效率。为了解决该问题, 研究了1种考虑关键路径序列的干道绿波协调控制方法。利用路径流量分担率和行程时间指数计算各车辆行驶路径的重要度, 并采用系统聚类算法识别干道上车辆行驶的关键路径。在此基础上构建了考虑关键路径序列的干道绿波协调控制模型: 考虑了各关键路径信号相位之间的协调关系, 设置了含0-1变量的信号相位矩阵, 并构建模型的基础约束条件; 设置了无效带宽存在性判断变量和最小重要度判断变量, 构建了考虑路径重要度的绿波带宽分配策略, 确保绿波带宽优先分配给重要度大的关键路径; 以关键路径序列加权绿波带宽总和最大为优化目标, 构建了模型的目标函数。利用VISSIM仿真软件搭建仿真环境, 以武汉市中山路4处交叉口组成的干道路段为例进行仿真验证。实验结果表明: 相比于传统的干道绿波协调控制方法和干道多路径绿波协调控制方法, 考虑关键路径序列的干道绿波协调控制方法使得干道平均延误分别减少了12.1%和4.8%, 平均排队长度分别减少了13.6%和7.6%, 平均停车次数分别下降了16.5%和9.7%;各关键路径的车辆平均行程时间与自身重要度大小严格成反比, 避免了绿波带宽的浪费。 

A Coordinated Green-wave Control Method on Arterial Roads Considering Critical Path Sequence

Traditional coordinated control method on arterial roads usually takes the maximum efficiency of the coordinated flows as the optimization objective. However, uncoordinated flows may be comparable to or even higher than the coordinated flows during certain periods, which can significantly deteriorate the overall efficiency of road operation in the actual fluctuated traffic flow environment on arterial roads. To solve this problem, a coordinated green-wave control method for arterial roads considering critical path sequence is proposed. The identification of the critical path sequence on the arterial road is calculated by the systematic clustering algorithm, and two indexes of traffic sharing rate of its path and travel time index are used as clustering parameters. On this basis, a coordinated green-wave control model for arterial roads considering critical path sequence is established. Firstly, the coordinated relationship among the signal phases of each critical path is considered, the signal phase matrix based on 0-1 variables is developed, and the constraints underlying the model are proposed. Secondly, the indicators for invalid bandwidth existence and the minimum importance are set, respectively, and a bandwidth allocation strategy for green wave considering the path importance is developed to ensure that the bandwidth of green wave is allocated to the critical path with a high importance in priority. Finally, the objective function of the model is established with the maximum weighted sum of green-wave-bandwidth of critical path sequences as the optimization objective. The simulation environment is developed using VISSIM simulation software where an arterial road section consisting of four intersections on Zhongshan Road in Wuhan City is used as a case study. The experimental results show that compared with the traditional coordination control methods for arterial green wave and arterial multi-path green wave, the proposed method results in a 12.1% and 4.8% reduction in the average arterial delay, 13.6% and 7.6% reduction in the average queue length, and 16.5% and 9.7% reduction in the average number of stops, respectively. Besides, the proposed method makes the average travel time of each critical path be strictly inverse proportional to its own importance, which avoids the waste of bandwidth of green wave.