Formulation of braking behaviors of expert driver toward automatic braking system

Deceleration patterns of an expert driver will be formulated as an example of comfortable braking pattern. The difficulty of its formulation is how to extract characteristics of the deceleration behavior. This research focuses on visual control of vehicles in car following. We have hypothesized that driver evaluate risk of collision based on the area change of the preceding car on the retina and determines his/her braking operation. Based on the hypothesis, an expert driver´s deceleration patterns will be formulated using the proposed risk perception index with visual information. It will be shown that the formulated braking pattern can generate smooth deceleration profile for many conditions of relative velocity and brake initiation timing uniformly with very simple calculation and without collision under some assumption. In addition, the model can determine brake initiation timing by specifying limitation of deceleration.