Research On Urban Multi-modal Traffic Assignment Problem Under Advanced Travel Information System

With the development and improvement of urban traffic system, people had more choice of travel modes and travel paths. During a trip, users could use only one travel mode or use many combined travel modes to complete the trip. As there are more and more travel modes to choose from, the number of routes which users can travel is also increasing. So, it is necessary to combine the urban multi-modal travel network as a whole, and then research travelers’travel choices under the whole network. The development of Intelligent Transportation System (ITS) has provided an effective way to reduce travelers’travel time and improve urban travel system. Advanced Traveler Information System (ATIS) as an important part of ITS, could provide travelers with abundant travel information, induce travelers to choose travel routes, and ease the traffic pressure. Based on the construction of urban multi-modal traffic network, the paper will analyze the components of travelers’ generalized travel cost, research how travelers will behave when having got travel information and when not, and then establish an urban multi-modal traffic assignment model and propose a solving algorithm. At the end of the paper, a model of traffic system optimization will be established under ATIS. The main work of the paper can be summarized as follows:(1) Analyze the characteristics of urban multi-modal traffic network, and then establish an urban multi-modal traffic network model based on hyper-graph theory. On the basis of the model, build generalized travel cost functions of each travel mode.(2) Put forward the definition of viable path and algorithm to search viable paths. Based on the search result of viable paths, a traffic assignment model on the basis of Logit model will be established. Then propose an algorithm to solve the model.(3) According to whether to equip ATIS or not, travelers can be divided into two types. Analyze the travel behaviors of each type of travelers, and then establish a traffic assignment model under ATIS based on the search of viable paths. At last propose an algorithm to solve the problem and verify the validity of the model.(4) Analyze the problem of ATIS market share. Setting ATIS service price as decision variable, establish a model for system optimization in urban multi-modal traffic network under ATIS. The model is a bi-level programming, the objective function of upper model is to make the minimum total travel cost of the whole traffic network system, while underlying model express travelers’travel choices of travel modes and travel routes under ATIS. At last, an algorithm will be proposed to solve the bi-level programming, and a numerical examples will be given to verify it.