Dynamic Traffic Assignment Based Optimization And Simulation For The Evacuation Strategy Of Traffic Flow In Urban Special Event

With the fast development of China’s economy and the civil culture needs, many metropolises of China are granted more and more accesses to holding urban special events (USE). These events enhance city fame and enrich cultural lives, while impacting the urban daily traffic, because of the great travel demand they bring. Among those impacts, the travel demand of the evacuation process of USE usually do a tremendous harm to the urban traffic, due to its short-time and sharp feature, which could even lead to an huge traffic tie-up.To plan the evacuation traffic flow of USE scientifically, predicting the occurrence, propagation and scattering of traffic jam has becoming a compulsory of the organizer of USE. On the past research of evacuation, the matching of traffic demand and the capacity of road network was studied qualitatively, which offered a management scheme. However, along with the development of intelligent traffic system (ITS), more traffic information can be gathered, and more guidance order can be delivered. Therefore, an accurate and quantitative evacuation plan is urgently needed.In this thesis, the current state of the research of USE traffic and regional evacuation is studied. The importance of the evacuation management in the USE is analyzed, and an integrated regional evacuation traffic management modeling framework is presented.Secondly, on the traveler behavior, the development of dynamic traffic assignment (DTA) theory is reviewed. Cell transmission model is introduced to improve the computational efficiency. The constraints of traveler behavior fit to large scale evacuation network are proposed. A linear programming model and a variational inequality model are put forward from a perspective of system optimal and a perspective of user optimal respectively.Thirdly, an instance of evacuation network was created according to Shenyang Olympic Stadium, and stored as a series of standard geographic files by TransCAD. Procedure of transferring road network into cell-connector network is designed. After that, the performance of the evacuation network in different scenarios is studied, especially the proper length of cells, the different importance of the bridges and the tunnel over the Hun River and the performance facing emergencies.Finally, a USE evacuation simulation platform is constructed, on which, the result of DTA could be displayed automatically.From the road transportation view, this paper adopts the optimization theory, CTM theory and system science to deeply study the problem of transportation regional evacuation traffic management. The research results not only can compensate for defects in emergency management theory, but also to enhance traffic management department emergency response capability, crisis management capacity and improve the USE organizing ability. Hence, this research has important theoretical significance and practical value.