Patent ID: 7259661

Claim:
A collision warning method for a vehicle, the vehicle having a device for measuring the distance from the vehicle to a second vehicle traveling ahead and a control unit programmed to generate a warning when a danger of collision of the vehicle and the second vehicle is determined, the method comprising the steps of: repetitively calculating in the control unit a deceleration rate for the vehicle sufficient to maintain a preselected distance between the vehicle and the second vehicle when the vehicle is decelerated subsequent to expiration of a braking reaction time of the driver of the vehicle, the calculation being based at least in part on a relative speed of the vehicle and the second vehicle, the distance between the vehicle and the second vehicle, a deceleration rate for the second vehicle and the preselected distance; repetitively comparing the calculated deceleration rate for the vehicle against a deceleration rate associated with vehicle braking initiated by the driver of the vehicle; and generating a collision warning signal when the calculated deceleration rate for the vehicle exceeds the deceleration rate associated with vehicle braking initiated by the driver of the vehicle; wherein the deceleration rate for the vehicle “a subject vehicle demand ” is calculated according to: a subject ⁢ ⁢ vehicle ⁢ ⁢ demand = - dv 1 2 2 · ( dx 1 - dx remaining ) + a front_ ⁢ 0 where: dv 1 =the relative speed of the vehicle and the second vehicle at the expiration of the braking reaction time of the driver of the vehicle, dx 1 =the distance between the vehicle and the second vehicle at the expiration of the braking reaction time of the driver of the vehicle, dx remaining =the preselected distance between the vehicle and the second vehicle at the end of deceleration of the vehicle, and a front — o =the deceleration rate for the second vehicle.