基于Wiedemann74跟驰模型的VISSIM排放测算适用性分析

Applicability of VISSIM to Emission Estimation based on Wiedemann74 Car Following Model

基于实测的西安市城市道路车辆行驶数据,在采用参数默认值的情况下,对比分析实测及仿真得到的速度、比功率分布,分析结果表明:不能将VISSIM仿真输出直接用于依托比功率的交通排放测算,需进一步对模型参数进行标定.采用遗传算法对模型参数优化,对比分析仿真与实测得到的跟驰后车比功率及排放因子.结果表明,通过遗传算法优化模型参数,可以显著减少比功率均方误差及排放因子计算误差.

Based on the collected driving data on urban roads in Xi′an city,the distribution of speed and vehicle specific power(VSP)obtained from real-world measurement and simulation were compared and analyzed with the default values of the model parameters.The results show that the VISSIM simulation output cannot be directly used to calculate the emissions based on the VSP,and calibration of the model parameters is needed.Then genetic algorithm was used to optimize the model parameters,and the simulated and measured VSP and emissions factors of following car were compared.The results show that the mean square error of the vehicle specific power and the calculation error of emission factors can be significantly reduced by optimizing the model parameters through the genetic algorithms.