Abstract:

In order to meet the practical demands for urban traffic management and control,the macroscopic traffic status of the West Third Ring Road network in Beijing as well as the corresponding time-varying characteristics and influencing factors is investigated based on the macroscopic fundamental diagram ( MFD) model of traffic flow and the monitored and simulated traffic data. In the investigation,first,the definition and vector algorithm of the MFD model are introduced. Next,the traffic-flow characteristic parameters of the network are calibrated based on the Van Aerde model. Then,the flow-density distributions in different periods are comparatively analyzed,and a hysteresis phenomenon of macroscopic traffic flow is derived. Moreover,the root cause of the macroscopic traffic status,namely the nonhomogeneous traffic density distribution in the network,is revealed. Finally,the effects of network structure,traffic demand and travel route on the traffic density distribution,the macroscopic traffic status and the traffic evolution of the network are analyzed through an Integration simulation. The results provide supports for the decision of macroscopic traffic control methods and congestion mitigation strategies.

Key words: macroscopic traffic status, macroscopic fundamental diagram, flow-density relationship, hysteresis phenomenon, traffic demand, travel route choice