Research On Variable Message Sign Location And Its Influence On Traffic Flow Distribution In Road Network

With the rapid development of economic society and the continuous growth of people’s travel demand,traffic congestion has become an urgent social problem to be solved.Practice has proved that the Variable Message Sign(VMS),as an effective group guidance information release system,plays an important role in easing traffic congestion and distributing traffic flow reasonably on the road network.However,the choice of VMS location lacks of systematic,scientific and reasonable demonstration.How to reasonably arrange VMS to maximize the reasonable induction of traffic flow in the road network,and how the location of VMS affects the distribution of traffic flow,these problems need to be further studied.Therefore,based on the VMS of main road of a city ring road,this paper optimizes its location,and studies the influence of VMS location on the road network traffic distribution and traffic operation state.Firstly,on the basis of considering the influence of traffic flow,traffic congestion index and attenuation degree of information on VMS site selection,considering the influence of the attraction ratio of alternative paths,the travel time and the cost of VMS installation on the site selection.Then the site selection optimization model of VMS is constructed by combining the utility and total cost of VMS.The traditional genetic algorithm and the improved genetic algorithm are used to solve the model.Finally,taking the ring road as an example,the best location of VMS is obtained.Secondly,based on the Stochastic User Equilibrium traffic distribution model,considering the influence of VMS induction information and VMS location on the driver’s path transfer behavior,a traffic distribution model based on different VMS locations under induced information is established,and the Method of Successive Averages(MSA)is used to solve the constructed model.Finally,taking the ring road in Xi’an as an example,the case analysis is carried out to obtain the traffic distribution situation of the road network without VMS,the current situation of VMS layout,and the optimal layout of VMS.Finally,VISSIM is used to simulate the road network traffic operation state of part of the road network \without VMS,VMS layout status,and VMS optimal layout.Data detection points are set for specific congested road.The average delay time and other evaluation index data under different induction conditions were collected to compare and analyze the influence of VMS location on road network traffic operation state and verify the effectiveness of the model.