Study On System Dynamics Model Of Beijing Traffic Structure Evolution

Urban traffic congestion has become a global problem faced by most big cities with urbanization and motorization. Countries gradually realize that reasonable transport structure is an important means of changing the status of transport. During the transition period of China's current urban transport structure, it has a positive meaning for addressing China's 21st century city traffic problem leading the city transport structure to a sustainable and reasonable model through scientific research. This paper is completed in this background and during the study of "the Beijing Municipal Traffic structural optimization" project, aimed at the establishment of the Beijing Municipal Traffic structural optimization system dynamics model and the application of this mode! in simulating traffic demand management, and other effects of the implementation of the policies. It also gives some practical policy recommendations for Beijing Municipal Traffic structural optimization.First of all, this article is clear on the issues and content, and gave a brief introduction about the applicability of the method of system dynamics which is used in the paper. It also introduces the characteristics and theoretical basis of system dynamics, plus with its basic modeling process of the method.Secondly, analysis the system structure The system boundary determination and factors analysis are done on the basis of study on traffic structure development in the history of the Beijing and the various factors impact on it . Determine the main system causal relationship chain and the causal relationship map between relevant variables, also doing the analysis on the system feedback loop.Again, construct system flow diagram on the basis of system structural analysis and the analysis of the causal relationship, establish Vensim language based system dynamics simulation model and the structure of the model formula, applied various methods on the model parameters determination .Finally, use the system dynamics model to simulate. Combining the Beijing Municipal Traffic Development in the annual report of the actual comparative statistical data model predictive results confirm the validity of the model; Use system dynamics simulation method to simulate the impact of policy variables changing on traffic structure and evaluate the reasonableness of the traffic structure from the perspective of road capacity and adaptability, the travel through a certain volume of traffic conditions different structure formation road load and from the road-building and road grading structure bearing capacity of the road will be compared to get the different road traffic state under different conditions of the road transport structure.