Traffic Dispersion Research On Changchun “Two Horizontal And Three Vertical” Expressway System

The appearance of expressway is the product of rapid development of urban traffic.Expressway system not only facilitates people's travel,but also stimulates the economic development of the whole region.The expressway system is called Expressway because of its high design speed,large capacity,no signal and high efficiency.However,due to the rapid development of the city,the rapid increase in the number of motor vehicles,resulting in the expressway attracts more and more vehicles,the phenomenon of traffic congestion occurs gradually,making the expressway gradually has a tendency to "low speed".Therefore,to ensure rapid,efficient,high capacity of expressway,it is imperative to solve the problem of traffic congestion in Expressway.Changchun "two horizontal and three vertical " expressway system completed during 2014,but in the past two years after opening gradually showed congestion.In order to give full play to the traffic function of expressway system,need to make traffic dispersion research on Changchun "two horizontal and three vertical" expressway system.Firstly,through on-the-spot investigation on the operation status of the "two horizontal and three vertical" expressways,the main congestion points are identified,and according to the main congestion node such as the connection section of exit ramp and entrance ramp with the ground traffic,traffic investigation is conducted and analyzed in detail.In view of the traffic jams often occur at the junctions of expressway entrance ramp and exit ramp,the traffic status of the expressway junctions is investigated,including the shunt traffic volume and confluence traffic volume.According to the influence range of the mixed traffic flow of the bridge down vehicles and ground vehicles,the range and survey contents of the traffic investigation are determined,including the traffic flow,the queue length and so on.According to the survey data,the traffic characteristics of ground key nodes and key nodes of the expressway are analyzed,including the characteristics of time-varying traffic volume,peak hour traffic characteristics and queuing length of key nodes,and then analyze the traffic flow capacity reduction of the ramp and ground lane.Then,according to the results of investigation and analysis,the causes of the "two horizontal and three vertical" traffic congestion are analyzed systematically,and the corresponding mitigation measures are put forward.According to the current situation of traffic,the causation analysis of expressway congestion is carried out on key nodes such as the roundabout of Nanhu Square,Freeway-Xiantai Street intersection and so on.Then,according to the different causes of congestion,the corresponding improvement programs are designed.At last,the traffic simulation and evaluation of the proposed scheme are given.Based on the survey data,the simulation models of the roundabout of Nanhu Square,Freeway-Xiantai Street interchange and Xiantai Street-Satellite Road interchange are established according to the proposed mitigation measures.Simulation results show the effectiveness of the proposed scheme.Through the above research and analysis,hoping to alleviate the Changchun "two horizontal and three vertical" fast road system congestion status,improve the operating efficiency of expressway.