Analysis On Traffic Influence Of Free Passage Of Changsha Ring Expressway

With the acceleration of the process of urban development,the expansion of the main urban area of the city,more and more attention has been paid to the development of urban transportation.As the city loop traffic,the high speed around the city can well alleviate the traffic pressure inside the city,making rational and efficient use of the ring expressway,it can improve the urban traffic efficiency,and promote the development of urban traffic space.Since its has been built and opened to traffic,the Changsha Ring Expressway has been serving the transit traffic in the urban area of Changsha,and greatly promoted the interaction between the internal and external traffic in Changsha.At present,Changsha Ring Expressway belongs to the expressway system,and the toll system is implemented,which restricts the demand for it in the urban area to a certain extent.Therefore,in order to improve the current traffic conditions in Changsha urban area,this thesis analyzes the influence of Changsha traffic network based on the free passage of Changsha Ring Expressway,and provides management methods and basis for the city managers.This thesis analyzes the traffic characteristics of the Changsha Ring Expressway and the current status of road traffic in Changsha City.Based on our country’s current high-speed toll mode to alleviate urban congestion,and the experience of toll-free traffic around the city in related cities in China,it is proposed a feasible plan for the toll free passage of Changsha Ring Expressway.It is necessary to build a traffic prediction model for the ring highway,because the thesis studies the traffic impact brought by the toll-free passage of the ring highway,the forecast of high-speed traffic around the city is the key research.The thesis compares a variety of traffic forecasting methods,and builds a forecasting model of high-speed traffic demand around the city,and it based on the traditional "four-stage" forecasting method.The thesis mainly studies the Xiang A-1 minibus,therefore,the traffic mode split is not considered in the four-stage forecasting process.A combined forecasting model was constructed for the forecast of traffic occurrence and attracting volume in the first stage,to reduce the limitations of a single method and make the forecast results more in line with reality.In the second stage,the traffic distribution uses the structural model method to carry out the traffic distribution,and the induced travel distribution model is used to obtain the induced traffic volume.The fourth stage of the traffic allocation method based on capacity limitation.For the existing OD data of the road section,the thesis constructs a bi-level programming model based on the current OD inversion,and uses the genetic algorithm to solve the problem using Matlab software programming,and obtains the OD inversion matrix with a smaller actual error.Considering relevant factors,and constructing an analysis model for toll free passage of the ring highway,to analyze the traffic changes of the ring expressway under the current toll free condition,and combine the constructed traffic prediction model and algorithm to carry out the traffic volume of the ring expressway under the toll free condition.prediction.According to the prediction results,it is concluded that the traffic volume of the highway around the city under toll-free traffic will show an increasing trend year by year.Then by using TransCAD to predict the traffic flow to simulate,and obtaining the traffic volume of the road section under free conditions in the future.Finally,the thesis comprehensively analyzes the traffic impact of the toll-free passage of the Changsha Ring Expressway,and puts forward the related problems and improvement suggestions of the toll-free passage of the Ring Expressway.