The Study On A Macroscopic Method Of Parameters Calibration In VISSIM

In recent years, the traffic problem is increasingly serious, the researchers set out to improve the existing road traffic capacity and intersection research to try to alleviate the urban traffic congestion. In the study of these problems is inevitable when applied to traffic simulation. There are a large number of parameters in the traffic simulation model which can affect the accuracy of the simulation model. And the parameters of city road system model mainly use the software default parameters in the model, so to determine the specific model parameters which suitable for traffic system of our country should to be solved. This article launches the research for the microscopic simulation model parameters calibration problem.This paper literature review introduces the research situation of domestic and foreign relevant parameters of microscopic traffic simulation model calibration, and then introduction of the microscopic traffic simulation model parameter calibration procedure, selection of evaluation index and the optimization algorithm.Finally focus on the parameters and vehicle driving behavior threshold in Wiedemann car models.Because the free flow can represent congestion and queue dissipation, this three kinds of traffic flow velocity pattern, the amount of information it is more complete, so to determine the evaluation index correction by microscopic traffic simulation model parameters are flow velocity pattern.Using the related knowledge dissimilarity measures to set the objective function used in this paper, using the two values image transformation, to calculate the difference between the flow speed graphs form simulation output and the flow speed graphs form the actual measured values.At the same time, for the highway model (Wiedemann99 model) and city road model (Wiedemann74 model), the simulation parameter calibration are analyzed.Finally, combined with genetic algorithm, set up the VISSIM, MATLAB and Excel Link integration platform, the VISSIM parameter correction process can realize automatic. According to the two different models of Wiedemann, respectively, on the highway, city road to do the data collection, and use this automatic correction system of parameters for each model. To prove that in the simulation process, the necessity of model parameter correction. According to the data of South Second Ring in Changsha,the typical Wiedemann car threshold curve fitting, and get the actual transportation of vehicle threshold graph.