基于最大流增流关键边的疏散逆向路段优化

Optimization of Contra-flow Links in Traffic Evacuation Based on the Critical Edge for Improving Maximum Flow of a Network

逆向车道作为提高路网疏散通行能力的一种交通组织方法,已在疏散交通组织中得到了广泛应用.本文采用网络优化技术,研究疏散交通组织中逆向车道设置路段的选择问题.将道路网抽象为有向网络,给出网络最大流增流关键边的定义,通过寻找网络最大流增流关键边、次关键边等,确定路网中实行逆向车道管理的备选路段.在求解最大流问题的最大容量路算法基础上,给出了在有向网络中寻找最大流增流关键边的改进算法,通过一个数值算例进行分析,并对计算结果进行仿真验证.结果表明,在产生大量交通需求的大规模交通疏散中,通过对最大流增流关键边所对应路段进行逆向管理扩容,能够有效压缩疏散时间.

Contra-flow got effective application in traffic evacuation as a method of traffic organization The problem of choosing contra-flow links in traffic evacuation is studied with network optimization technique. A road network is abstracted as a directed network, and the critical edge for increasing the maximum flow value of a network is defined, and alternative links for contra-flow can be got by searching critical and sub critical edges etc. for increasing the maximum flow value. A modified algorithm is presented to find such critical edges on the basis of the maximal capacity path algorithm for the maximum flow problem. A numerical example is given and the effects are tested through traffic simulation. The results show that evacuation time can be effectively decreased through increasing the capacity of critical links by contra- flow in large-scale evacuation.