Driver Collision Avoidance Behavior under Differing Risk of Rear-End Scenarios

The Forward Collision Warning/Avoidance systems (FCW/CA) have been shown to be effective in avoiding rear-end collisions. In order to develop driver-acceptable FCW/CA systems, it’s important to understand how the drivers behave when involved in scenarios with different levels of risk of rear-end collisions. This study investigated the drivers’ collision behaviors using a simulated car-following task with different initial headway and Lead Vehicle’s (LV) decelerations. Drivers in the experimental condition drove a Renault Megane III mounted on the high fidelity Tongji Driving Simulator with 8-degrees-of-freedom. The experiment was a four-factor experimental design, mixed between and within subjects. A total of 30 drivers were asked to take either braking or steering maneuver to avoid the collision when a lead vehicle braked at initial headway distances (1.5sec and 2.5sec) and different decelerations (0.3g, 0.5g, and 0.75g). The ANOVA with repeated measures were used to compare the collision avoidance behaviors of the subjects across different conditions (initial headways × deceleration). The results indicated that a) drivers’ perception response time was significantly lower under low headway conditions; b) drivers significantly release accelerator faster under short initial headway conditions; c) the driver started braking faster when under high risk conditions (short initial headways or large LV decelerations); d) experienced drivers tend to have faster response time compared to the novice drivers. Meanwhile, the propensity of braking or steering maneuver to avoid the collision was analyzed. The result of this study can be applied to the future design and improvement of well driver-accepted FCW/CA systems.