重大事件下的路网交通疏散双层优化模型

Two-tier optimization model for road network traffic evacuation under major events

针对城市中重大事件期间的交通出行特点,提出基于交通组织的上层优化算法与基于信号控制的“绿波”与“红波”下层协同优化算法,其中对于静态的交通组织优化方案不能及时响应动态疏散需求的问题,通过在时间维度的离散化对上层算法进行优化;根据上层优化结果相应地调整信号控制策略,考虑关键路段的蓄车能力来限制信号周期以及路口可能发生的绿灯空放现象和车辆溢出现象来确定相位差设计范围;并以整体延误最小化、交通通行能力最大化作为优化目标建立路网交通双层优化模型。仿真结果表明,该模型下主要道路交叉口的通行车辆数平均提高7.1%,同时5个道路交叉口的车辆总延误平均减少5.8%,验证了模型在应对重大活动事件造成的道路交通拥堵有更佳的适用性。

According to the characteristics of urban traffic during major events,this paper proposed the upper level optimization algorithm based on traffic organization and the lower level collaborative optimization algorithm based on the“green wave”and“red wave”of signal control.Considering that the static optimized scheme was unable to respond to the demand for dynamic evacuation in time,the upper level algorithm was optimized by the discretization in temporal dimension.Signal control strategies were adjusted according to the upper level optimization results.The signal period was limited by considering the vehicle storage capacity of key road segments,and the phase difference design range was determined by considering the possible green light empty phenomenon and vehicle overflow phenomenon at intersections.With minimizing the overall delay and maximizing the traffic capacity as the optimization objectives,a two-tier optimization model of road network was established.The simulation results show that the number of vehicles passing through the main road intersections is increased by 7.1%on average,and the total vehicle delay of five road intersections is reduced by 5.8%on average,which verifies that the model has better applicability in dealing with road traffic congestion caused by major events.