System Dynamics Model of Urban Transportation System and Its Application

Urban transportation system is a complex system with multiple variables and nonlinear feedback loops and influenced by transportation, social, economical, and environmental factors. Conventional transportation modeling approaches are unsuitable to simulate and evaluate its performance. This paper presents a system dynamics approach based on the cause-and-effect analysis and feedback loop structures. The proposed SD model comprises 7 submodels: population, economic development, number of vehicles, environmental influence, travel demand, transport supply, and traffic congestion. The model runs in Vensim PLE software using the data from Dalian, China. The coefficient of the intervention policy of vehicle ownership is chosen as the control variable for simulation, and the impacts of different policy scenarios on urban development and transportation system are analyzed. It suggests that Dalian should restrict the total number of vehicles to improve the sustainability of transportation system.