Research On Calibration Method Of VISSIM Simulation Parameters Considering Safety Index

Signalized intersections have always been the focus of the traffic research.It’s an important method to analyze urban signalized intersections by traffic simulation technology.General used microscopic traffic simulation software is based on foreign traffic environment,and its driving behavior parameters are not applicable for the traffic environment in China.Therefore,it’s a positive effect for Chinese traffic simulation engineering to research the calibration method of driving behavior parameters.Through the domestic and international literature,the current calibration of the driving behavior parameters of the microscopic traffic simulation model has the following problems: 1)The objective function for calibration only considers the efficiency evaluation index,and does not consider the safety evaluation index that can more directly reflect the operating state of the vehicle.It makes the calibration result unsatisfactory when establishing a safety analysis-oriented traffic simulation model.2)Most of the domestic VISSIM parameter calibration methods are only for the version before VISSIM6.0,but the new version has updated the secondary development syntax and opened more parameter interfaces.Based on the above two points,this article has carried out the research of the simulation model parameter calibration method considering the safety index.First,I report on the process of building a traffic simulation framework for safety analysis,VISSIM simulation principle and traffic conflict technology is introduced.Then,after analyzing the impact of driving behavior parameters in VISSIM on travel time,queue length,and traffic conflicts,and the calibration set parameters were determined: average parking distance,safety distance plus part,safety distance multiple part,maximum deceleration,and minimum headway distance.On this basis,a calibration model with the relative error of travel time,the relative error of queue length and the relative error of traffic conflict as the objective function is established.Finally,through the VISSIM.COM secondary development interface,the parameter calibration process is solved with the help of genetic algorithm,and the calibration process is automated by programming.The rest of the thesis is an example of establishing a microscopic traffic simulation model about Shuhan Road in Chengdu.Using the parameter calibration algorithm established in this paper,I calibrate the parameter by one of the signalized intersections.and found the objective function weight coefficient after comparing the calibration results under different conditions of the objective function weight coefficient in the calibration algorithm.Comparing the calibration results of this paper with the calibration results of other documents that have not considered safety index,it is found that the calibration results of this paper are effective in safety-oriented simulation models.