基于模糊旅行时间的动态交通分配模型

提出了一种新的模糊动态交通分配(FDTA)模型,采用模糊集合理论描述动态旅行时间,应用模糊h截集的最短路径方法找出模糊最短路径集合,计算各条路径的隶属函数,并采用C-LOGIT模型实现网络加载,最后比较了FDTA模型和经典的随机动态交通分配(SDTA)模型.仿真结果显示:在正常交通状况下FDTA模型能够获得与SDTA模型非常接近的分配结果,并更加符合实际的交通状况;当有交通拥堵、事故、施工/管制等动态交通状况发生时,FDTA模型能够解决动态交通状况的建模问题;当交通网络结构复杂时,通过改变h值可以有效减少模糊最短路径的数量,提高计算效率.

Dynamic traffic assignment model based on fuzzy travel time

A new fuzzy dynamic traffic assignment(FDTA) model was proposed.Firstly,the fuzzy theory was used to describe the real-time link travel time and path travel time.Secondly,fuzzy shortest path sets were found based on h-level sets,and then their membership functions were calculated.Thirdly,the CLOGIT model was used for network loading.At last,FDTA model was compared with classical stochastic dynamic traffic assignment(SDTA) model using a small traffic simulation network.The simulation results show that FDTA model can achieve more reasonable network traffic flow,and theoretically resolve the problem of traffic network dynamic traffic flow modeling as the congestion,traffic incidents or construction happened.Further,when the traffic network becomes complex,by changing the value of h,the number of fuzzy shortest paths could be decreased and the computation efficiency could be improved greatly.