Large-scale Traffic Simulation And Validation Of Link Travel Time Estimation Model

With the rapid growth of car ownership,the traffic problem in large and medium cities will be more severe.Among many ways to study traffic congestion problem,infrastructure building and traffic demand control measures are difficult to effectively alleviate the traffic problem because of their inherent defects;while traffic simulation technology is widely applied due to its flexibility,low cost and repeatability.Nevertheless,small-scale traffic simulation usually simplifies the inherent complexity of traffic circumstance,and reduces the scientificalness and preciseness of research.This paper establishes large-scale transportation simulation model,proposes the joint use of macroscopic traffic simulation and microscopic traffic simulation method to establish the simulation model,in order to achieve the ideal simulation results.On this basis,this paper studies the reliability of travel time estimation model,and promotes its practical application further.First of all,regarding the electronic traffic map of Luohu District,Futian District and Nanshan District in Shenzhen City as template,this paper uses VISUM macroscopic traffic simulation software to build large-scale transportation simulation model,including the establishment of traffic supply model,the establishment of traffic demand model with the Standard 4-Phase Method and static traffic assignment.In the process of simulation,this paper makes a proper simplification of the road network and intersection in Shenzhen city.Secondly,in this paper,the large-scale traffic simulation model is introduced into the VISSIM micro simulation software,and the static allocation result is used as the initial state of the dynamic assignment.By setting the parameters of the traffic demands,this paper simulates the early peak traffic,and by debugging the dynamic simulation parameters,this paper studies the effect of the different parameters on the dynamic allocation process and results.Ultimately,this paper carries out dynamic traffic assignment,and gets the vehicle traveling data.Finally,this paper makes the structure design and arrangement to the data of link network and vehicle travel,and then inputs the arranged data into the link travel time estimation model proposed by Li Qiang.et al,programming to estimate the link travel time and verify the reliability of the travel time estimation model.The experimental results show that the model is reliable and anti-interference when the vehicle traveling time obeys the two-peak distribution,but not reliable in the three-peak distribution.