Macroscopic traffic flow: a modeling and simulation study considering impedance characteristics

The paper studies macroscopic traffic flow modeling and its verification analysis of urban expressway main line and its ramp. Firstly, the paper compares the Isotropic dynamic models and the Anisotropic dynamic models. It founds the conceptual model of macroscopic traffic flow based on the car-following model, viscosity and compressibility of traffic flow and the mathematical model of macroscopic traffic flow by improving on traditional simplified processing way, which takes dynamic modeling method and introduces the viscosity term and compressibility term of traffic flow, according to evolvement from micromodel to macromodel. In addition, in order to simulate and evaluate the macromodel, "simple simulation scenario" of North-South Elevated Expressway in Shanghai, from Yan'an East Road interchange to Tianmu Road rotary interchange, has been established in the paper. The simulation results showed that the traffic flow volume – velocity - density relationship of improved macromodel is in line with the expected results. And the model correctly describes the actual traffic operation.