Research On Traffic Evacuation Strategies For Emergent Public Events

In recent years, along with the advancement of urbanization at home and abroad, various emergent public events, especially natural disasters and accidents, happened in many cities. Some disasters, such as dangerous chemical leaking or explosion, will cause large-scale evacuation of crowds. In order to cope with these emergent public events, we need to do researches on traffic evacuation in case of emergent public events.Firstly, this thesis reviews current domestic and foreign scholars' researches on traffic evacuation for emergent public events. Secondly, some analysis models are built for emergency transportation resources optimization arrangements and evacuation travel demand forecast based on operation research theory. And the thesis has provided an improved time-dependent curve function of evacuation travel demand. Thirdly, dynamic traffic assignment model is used as the traffic evacuation model. Then this thesis analyzes this model's structure and its optimized conditions. At the same time, the link capacity dynamic adjustment method in this model is also provided. Finally, this study takes the chlorine leak blasts in Chongqing Tianyuan Chemical Industry Plant as the case-study, and selects TransCAD software as the traffic evacuation simulation platform to build the foundational roadway network around this plant. By using the transportation problem procedure, the travel demand OD matrix for static evacuated personnel in the affected scope is determined. Then this OD matrix is converted into dynamic OD matrixes with the evacuation travel demand time-dependent curve function. Based on the above mentioned work, dynamic traffic assignment is implemented to simulate the traffic operation properties on the roadway network. Then some key links' outputs from this simulation result are analyzed and some suggestions for traffic evacuation are provided.Through this study, we can get a set of quantified research approach on traffic evacuation for emergent public events, which can provide a scientific and effective technical support for the decision-making on traffic evacuation of the transportation sector.