Automatic Braking Method for Collision Avoidance and Its Influence on Drivers Behaviors

Collision avoidance system with automatic braking has been developed to prevent rear-end crashes. It is pointed out that driver's behaviors could be changed by introducing such collision avoidance systems. Thus, it is important to understand the driver's behavioral changes with such systems and to apply the results to its better design for effective use of the assistance system. On the other hand, a deceleration assistance control for collision avoidance based on driver's perceptual risk has been proposed. This system has an advantage that activation timing of the automatic braking can be changed by changing a parameter in the control method that allows the system to generate deceleration profile uniformly without any complex calculation. In this paper, an automatic braking method in which the activation timing is changed by its individual differences was introduced. The effect of the braking activation timing of the system on the driver's behavioral changes was investigated using a driving simulator experiment. The results demonstrated that the activation timing strongly affect the drivers behavior in time headway in following situations and drivers' braking timing when the lead vehicle's sudden deceleration as well as the gazing behavior in preparation of lane-changing operation.