基于MFD的路网可扩展边界控制策略

Scalable Perimeter Control Strategy of Road Network Based on MFD

为了缓解城市路网中区域性的大范围交通拥堵,基于宏观基本图的相关理论,提出了一种针对过饱和路网的可扩展边界控制策略。该控制策略以提升路网整体运行效益为目标,具体方法分为两步:首先是考虑堵塞区域边界节点上游路段的储存车队能力,避免边界路口上游路段排队溢出,建立边界控制的约束条件,确定反馈"闸门"的控制位置,通过实时动态调整堵塞区域的控制边界,形成一种新的扩展边界;然后建立区域反馈控制模型,在堵塞区域扩展边界路口设置反馈"闸门"限制车流进入堵塞区路网,维持堵塞区路网车辆总数在一个合理可行范围内,从而使被控区域保持高效运行。为验证该策略的有效性,以Sioux Falls测试路网为研究区域,运用Vissim仿真软件对实施该控制策略前后的路网运行情况进行了对比分析。研究结果表明,在可扩展边界控制策略实施后,路网各项运行指标均有明显改善,大范围的交通拥堵状况得到明显缓解,并且不影响边界外的路网运行效率。在整个仿真分析时段,路网平均延误时间降低约35%,路网平均速度提高约30%,路网平均出行时间减少约15%,平均停车次数减少约30%,离开路网的车辆数增加约13%。

In order to alleviate regional traffic congestion over large areas in urban zonal road network,a scalable perimeter control strategy for over-saturated road network based on the theory of MFD is proposed.The control strategy aims at improving the overall operation efficiency of the road network. The specific method is divided into 2 steps. First,it considers the fleet storage capacity in the upstream section of the boundary node in the congested area and avoids queuing overflow,establishes the constraint condition of boundary control,determines the control position of feedback gate,and forms a new extended boundary by dynamically adjusting the control boundary of the congested area in real time. Then,it establishes a regional feedback control model,and set the feedback gate at the extended boundary junction of the congested area to restrict the traffic flow into the congested area,which maintains the total number of vehicles in the congested area within a reasonable range,so that the controlled area can maintain operation efficiently. In order to verify the effectiveness of the strategy,the Sioux Falls test network is used as the research area,and the performance comparison of the network before and after the strategy is conducted by using Vissim simulationsoftware. The result shows that（ 1） the implementation of the scalable perimeter control strategy has improved the operation index of the road network,a wide range of congestion is obviously alleviated,and the operation efficiency of the road network outside the boundary has not been affected;（ 2） during the entire simulation analysis period,the average delay time of the road network decreased by 35%,the average vehicle speed in the road network increased by about 30%,the average travel time in the road network decreased by about 15%,the average number of stops decreased by about 30%,and the number of vehicles out of the road network increased by about 13%.