A car-following model for urban traffic simulation

摘要

This paper describes a car-following model specifically developed for urban interrupted traffic situations in microscopic simulation models with one-second scanning update time. The model is based on a desired spacing criterion which is assumed to be a linear function of the speed. Analysis of data obtained by video recording of vehicle platoons in the Sydney CBD has shown that desired spacing is an individual driver characteristic and that drivers have different desired spacings in acceleration and deceleration. The proposed model eliminates the problems associated with the apparent reaction time inherent in previous models, while the use of distinct desired spacing characteristics for acceleration and deceleration reproduces the observed hysteresis loops due to the reaction delay in the acceleration phase. The model ensures a smooth transition from the unconstrained to the constrained situation as a follower vehicle gradually approaches the leader. The model has been validated for urban interrupted flow conditions in the speed range from 0 to about 60 km/h. The desired spacing parameters were collected for passenger cars only; for heavy vehicles, the current parameters are estimated based on assumptions using information from other sources. Further development work is intended to concentrate on calibration of the desired spacing characteristics for various combinations of vehicles in urban flow conditions, and on extending the model to the higher speed range of rural highways and freeways.