Forward obstacles collision warning system based on deceleration for collision avoidance

In our previous study, we proposed a deceleration for collision avoidance (DCA) as an index to evaluate a collision risk against forward obstacles. The calculation process of DCA assumed that a following vehicle performs an uniform motion within a driver´s constant reaction time; the assumption causes underestimation of the collision risk when the following vehicle accelerates and overestimation when it decelerates. This paper shows an improved calculation method of DCA based on an expanded assumption that the following vehicle keeps an uniformly-accelerated motion within the reaction time. The numerical simulation is performed to show that the improved DCA evaluates the collision risk properly compared to the conventional DCA, and driving simulator experiments are conducted to verify the effectiveness of a forward obstacles collision warning system (FOCWS) based on the improved DCA.