Network Traffic Congestion Evolution Research Based On Macroscopic Fundamental Diagram

With the deepening of the urbanization process,urban area is expanding.Urban traffic congestion is developing from an isolated point to a network area.The effect of single point of congestion control measures is getting weaker.So the development of traffic congestion from the network level is the current problems in Urban Traffic Congestion Research.In this paper,based on the Macroscopic Fundamental Diagram of the congestion evolution law research method,to determine network traffic congestion from the macro point of view of network.Then,according to the shape of MFD,to division the traffic network state and and to analysis the evolution between them.This paper has made the following achievements:(1)On the basis of summarizing the research results of congestion law and the characteristics of MFD,the method of congestion law based on the MFD is adopted,and the bearing capacity of the road network is calculated according to the MFD.The threshold is determined,and the congestion state of the network is judged by combining the MFD shape,and the evolution mechanism between the traffic states of the road network is analyzed.(2)Based on the network of Jiashan city,the research method of congestion law based on Macroscopic Fundamental Diagram is verified.According to the data obtained from the simulation results,the MFD of the simulated network is drawn,and the results of the network traffic flow are verified and analyzed.(3)Based on the MFD model,the influencing factors of traffic congestion are analyzed.The main factors of the analysis are signal control,traffic flow composition and road network key node capacity.(4)A double-cycle signal coordination control model is proposed for the Y-type intersections in the urban network.The model is applied to the actual network in Yiwu.The practical application shows the effectiveness of the model.Using the simulation software,the effect of model control is evaluated based on the MFD.