Dynamic Analysis And Research On The Vulnerability Of Urban Road Traffic Network In Traffic Congestion

In recent years,with the frequent occurrence of destructive incidents such as traffic jams,the city’s road traffic system network has failed on a large scale,fully exposing the vulnerability of the road network.This article aims to analyze the causes of traffic congestion,the propagation process,the basic structure of the road traffic network and the influencing factors of the vulnerability of the urban road network,combined with the propagation process of the traffic congestion state,dynamically evaluate the vulnerability of the urban road network,and Based on the characteristics of traffic flow operation,measures to reduce the vulnerability of urban road networks are proposed.The paper analyzes the characteristics and laws of the propagation process of traffic congestion by the Gaussian plume model,and considers the changes in vulnerability and congestion degree during the cascade failure process caused by congestion in the road network segment.From the perspective of traveler time loss,the vulnerability evaluation index is established as a cumulative and time-varying index,and the traffic flow redistribution model under the cascade failure condition is combined with the cell transmission model to construct the urban road network vulnerability dynamic evaluation model.The vulnerability analysis is carried out on part of the road network in Lubei District of Tangshan City.By setting up interference events of different road sections and different degrees of influence,and then combining the change process of traffic flow state parameters,the analysis and evaluation are carried out.The research results show that when the main road section with large traffic flow fails,the road network will have a large cumulative and time-varying vulnerability.The initial time of the damage event,the evaluation index has a clear trend,and as time progresses,the evaluation The indicators begin to gradually stabilize;compare the complete failure and partial failure of the road section,when there is sufficient traffic capacity,the damage event will not have a significant impact on the road section;analyze the vulnerability of the exposure and the vehicle arrival rate from the traffic flow.Decrease and increase in vehicle density show a positive correlation.According to changes in traffic flow,an effective control strategy to reduce the vulnerability of the road network is proposed.