Influences of dynamic safe headway on car-following behavior

In car following states, the reaction of drivers is closely related to the space headway at given speed difference. Unlike the constant velocity difference reaction coefficient in traditional traffic model, this work designed a dynamic function, which can realize the switch between models according to the dynamic headway between vehicles, and developed a new car-following model to investigate the influences of dynamic safe headway (DSH) on car-following behavior. First, the following behavior of vehicle with DSH under urgent situation is simulated to demonstrate that DSH has the ability to prevent the occurrence of collision. Then, the prediction of delay time of car motion and the kinematic wave speed is reasonable and the evolution from free flow to congested flow is well reproduced. In addition, the result of excitation simulation shows that DSH can absorb the disturbance and suppress the propagation of traffic oscillations effectively, which is hard to achieve for traditional traffic model. Finally, the numerical experiment under period condition demonstrate that the new model is conducive to improving driving performance and further to smooth traffic flow. In addition, calibration and validation results show that the empirical data can be modeled with a quantitative agreement. (C) 2021 Elsevier B.V. All rights reserved.