Research On Urban Multi-modal Traffic Assignment And Algorithm Problem Based On Path Constraint

In recent years, with the expansion of the city circle and the continuous improvement of the urban infrastructure, the travel mode of urban residents has changed from single to multimode. The research of multimodal transport system is mainly focused on the system consisting of cars, buses, subways and bicycles. As a kind of new energy vehicle, pure electric vehicles, due to environmental protection and energy conservation is loved by people, and gradually come into people’s lives. The widespread use of electric vehicles has changed the original flow distribution on the road. Therefore, the electric vehicle is joined into the multimode traffic system. Considering the actual situation, not each path is chosen by travelers. Only when the transfer times, travel distance, generalized cost and other restrictions of the path accord with travelers’ requirements, this path will be chosen. So the transfer times, the electric car travel distance, the generalized cost of the travel path constraint should be carried on restraint, and redefining feasible path and effective path, the paper studies the path searching algorithms and traffic assignment model under the path constraint. The main work of the paper can be summarized as follows:(1) Analyze the characteristics of multimodal traffic network, and establish a multimodal traffic system based on the hyper-network theory, including five modes of transportation, cars, electric vehicles, buses, subways and bicycles.(2)In the multimodal network, for the traveling distance, the transfer time, the generalized cost of the path, the concept of feasible path and effective path are redefined. The feasible path filter algorithm is proposed based on the K shortest path. The improved shortest path searching algorithm based on Dijkstra algorithms, and the effective path searching algorithm are proposed.(3) Establish generalized cost model and analyze the cost function of each arc in multi-modal network. Traffic assignment model and algorithm based on UE, and a numerical example are proposed.(4) According to effective path searching algorithm, search the effective path in multi-modal transportation network and load the road traffic flow based on Logit model. The model and algorithm based on the stochastic user equilibrium assignment is proposed, and the results of flow distribution and the sensitivity of parameters are analyzed, according to the example.