Study On Parameters Calibration Of VISSIM Traffic Simulation Model

With the rapid development of the city, private car ownership is increasing year byyear, traffic congestion problem has aroused great concern to the relevant departments inmany cities. The microscopic traffic simulation software is a powerful tool to evaluatetraffic solution, so the accuracy of the model is very important. At present, the trafficsimulation software used by the most of our research institutions are imported fromabroad, so carrying out model parameters calibration according to the actual traffic operationcondition in our country on the software model parameters calibration is the prerequisite andfoundation to perform other work. The common algorithm ofmodel parameter calibration isgenetic algorithm, but the genetic algorithm will cost a lot of time in the iterative process. Atthe same time, most of the parameter calibration methods are separate programs, and have notrealized the parameter correction automatically. Based on the above two issues, the thesis hasimplemented a new method of automatically parameter calibration program for VISSIM. Inthis thesis, following work has been finished:Firstly， the thesis provides an overview of microscopic traffic simulation,and summarized the current research status. The research orientation for parametercalibration is along two main lines, and the focus of this thesis is on the research for the modelcalibration algorithm. In this thesis, the core parameters of car following model andlane-changing of VISSIM are introduced in detail, and then, the method of choosingevaluation index and parameter for calibration were analyzed.Secondly, the thesis take genetic algorithm as parameter calibration method, and usingthe trained generalized regression neural network to predict the output of VISSIM, that canavoid the waste of time in the iterative process of genetic algorithm. After that, a case studyof the Zhong Guan Street intersection in Beijing is carried out, the above parametercalibration method is verified. The results show that, this method can effectively improvethe efficiency parameter correction, and can meet the requirements of the accuracy of themodel.Then, automatic parameter calibration system of VISSIM traffic simulation software isestablished, realizing the automation of parameter calibration. Users can control the parameter calibration process through a simple graphical interface, and obtain visual contrast.Finally, a case study of the Ling Hu Dao Dao intersection in Wuxi is carried out to verifythe reliability of the automatic calibration system. Average travel time is chosen as theevaluation index, based on floating car and field survey, traffic flow data was collected. Andthen simulation model is set up in VISSIM. The running results show that the system canrealize the user control of the model parameter calibration, and the accuracy of modelcalibration meet in an acceptable range.