A procedure for validation of microscopic traffic flow simulation models

Model verification and validation are two important tasks in developing a traffic simulation model. Traffic simulation models have unique characteristics because of the interaction among the drivers, vehicles, and roadway. The effects of the interaction on traffic flow should be considered in verification and validation of the models. If these two tasks are not properly performed, a traffic simulation model may not provide accurate results. A procedure for verification and validation of microscopic traffic simulation models is developed, and its application to a car-following simulation model, CARSIM, is demonstrated. The validation part of the procedure is emphasized. The validation efforts are performed at the microscopic and macroscopic levels. For validation at the microscopic level, the speed change patterns and trajectory plots obtained from simulation models are compared with those from field data. For validation at the macroscopic level, the average speed, density, and volume for simulated platoons are compared with those of field data. Also, variation of these parameters when the platoons go through a disturbance and interrelationships between these variables computed from the simulation models and the field data are examined. Regression analysis and analysis of variance of the simulation results versus the field data are discussed. The procedure may be considered as a step toward development of a comprehensive systematic approach for verification and validation of traffic simulation models.