Research on the evolution law of incidental traffic congestion based on CTM

Abstract

Abstract This paper takes the urban road network as the research object to study the temporal and spatial characteristics and evolution mechanism of incidental traffic congestion. Firstly, the improved cell transmission model (CTM) is proposed considering the traffic flow delay phenomenon and the boundary conditions of the cell at the intersection. Secondly, considering the delay time of vehicles at the intersection, the A * path-finding algorithm is proposed, and a dynamic path selection model based on real-time road impedance is established. Finally, combined with the improved CTM and dynamic path selection model, starting from the severity of the incident and the frequency of information induction and update, the traffic flow is simulated by MATLAB software to simulate the traffic flow in the road network under different conditions and analyze the diffusion characteristics of congestion under sudden events. The simulation results show that during the simulation time period, when the traffic capacity caused by the severity of the incident is only 1/2, 1/4 and 1/8 of the original, the maximum number of congestion cells in the network is 9, 26 and 35, and the maximum delay per unit time stepping is 290, 1.31*103 and 2.41*103 vehicles, and the total delay in the road network is 2.73*105, 7.19*105, and 1.50*106 vehicles, after 320δ, 578δ and 588δ the congestion cells in the road network completely disappear. At the information induced update time of 30s, 120s and 600s, the maximum number of congestion cells in the road network is 5, 10 and 23, the maximum number of delayed vehicles is 162, 254 and 985 vehicles - time stepping, the total delay is 1.25*105, 1.68*105 and 5.84*105 vehicles. The findings of the study can provide reference for urban road network design and traffic management.