A modified full velocity difference model based on time to collision as a safely indicator for braking state

Car-following models play an important role in the field of road traffic system, and one of its important issues is the vehicle formation. To conduct the analysis of braking state vehicle formation, this paper introduces the concept of inverse of time to collision and gives a detailed analysis the optimal velocity (OV), the modified optimal velocity (MOV), the full velocity difference (FVD), and the modified full velocity difference (MFVD) models. In this paper, we proposed a modified car following model based on the Full Velocity Difference (FVD) model, with the new optimal velocity as function of spacing and relative speed which introduced the weighting factor that based on inverse time to collision. The modified full velocity difference shows that can simulate the motions of cars is better than the modified OV model.