考虑信号配时引起延误的改进Frank-Wolfe算法

Improved Frank-Wolfe Algorithm Considering Delays Due to Signal Operations

针对用户均衡交通分配问题,提出一种考虑交通信号配时引起延误的基于Frank-Wolfe算法的路段交通量求解方法.在Frank-Wolfe原算法的基础上,将由信号控制所引起的延误以惩罚值的形式加入到阻抗函数中,通过更新后的路段阻抗,计算OD间的最短路径,然后根据“全有全无”加载方法获得的各路段交通量,计算步长,更新OD间所有已配流的路段的交通流量,最后确定出一组满足用户均衡规则的路段交通量.通过算例表明,改进算法可有效的用于路段交通量的计算,在计算的过程中能避免穷举交通网络中的所有路径,所得到的路段交通量也更加符合实际需要,可用于用户均衡交通的流量分配.

Facing the problem of user equilibrium traffic assignment,this paper proposes a method to solve link traffic flows considering delays due to signal operations.Based on the original Frank Wolfe algorithm,the delay caused by signal control is added to the impedance function in the form of penalty value.The shortest path between OD is calculated through the updated link impedance.Then,link traffic flowsare obtained according to the“All-or-Nothing”loading method,the step length is calculated,and the traffic flows of all the allocated sections between ODare updated.Finally,a group of link traffic flows meeting the user equilibrium rules are determined.The example shows that the improved algorithm can be effectively used in the calculation of link traffic flows.In the calculation process,it can avoid exhausting all the paths in the traffic network,and the link traffic flows obtained are more in line with the actual needs,and can be effectively applied to the user equilibrium traffic flow allocation process.