Research On The Evolution Of Urban Traffic Mode Structure Based On System Dynamics

The national large and medium-sized cities all face prominent traffic contradiction and appear serious urban traffic congestion, pollution and energy problems, which affect the production and life in the city and the development of economic construction. Under this background, the urban traffic mode structure optimization becomes the primary choice to solve the traffic problems in many big cities. The implementation of a series of urban traffic planning and development policy and preferred development of public transportation strategy can promote reasonable evolution of urban traffic mode structure.This thesis first analyzes the urban traffic mode structure in detail and their influencing factors. Based on system dynamics theory, the thesis determines the purpose and boundary of the model. The purpose of the study is to model the evolutional tendency of urban traffic mode structure and the effects of different traffic policies on urban traffic load, energy consumption and pollution of the traffic.According to the boundary of the system, it determines main factors and their causality diagram. On the basis of which, it renders the causality diagram of the urban traffic mode structure system dynamics model, and the flow diagram of the model after defining the variable type and determining the relationship of the variables. Considering urban traffic as the research object, this paper discusses the factors of urban traffic system including the social economy, people travel characters, traffic demand and supply, traffic energy consumption, traffic pollution, transportation policy, builds the system dynamics model of urban traffic mode structure and uses the case study of Shanghai to simulate the urban traffic mode structure evolutional trend under different policies. By changing the relevant policy variables, the thesis simulates the implementation effects, observes the change of urban traffic mode structure and traffic operation state under various traffic policy scenes and makes preliminary recommendations.Any single traffic policy has its limitations, comprehensive policy must be adopted, including public transportation priority policy, traffic planning and investment policy and traffic demand management policy must be combined with. The comprehensive policy can realize the ideal urban traffic mode structure optimization goal, and obviously improve the traffic operation conditions. This model verifies that traffic comprehensive policy can obviously reduce traffic congestion, improve the traffic operation conditions, reduce exhaust pollution and energy consumption, and optimize the traffic mode structure.