Patent ID: 8536994

Claim:
A collision detection unit that mounts to a host vehicle, the collision detection unit comprising: a housing; a stop lamp associated with the housing and visible from outside the housing, the stop lamp configured to display a first color; a warning lamp associated with the housing and visible from outside the housing, the warning lamp configured to display a second color different from the first color; a sensor associated with the housing, the sensor configured to detect an object and to provide a signal indicative of distance between the object and the host vehicle; and a processing unit located in the housing that, based on the signal, (a) determines a change in distance between the host vehicle and the object, (b) if there is a change in distance in step (a), determines a speed difference between the host vehicle and the object, and (c) compares the change in distance and the speed difference to threshold criteria; wherein the processing unit activates the warning lamp to display the second color based on the comparison of the change in distance and the speed difference to the threshold criteria; wherein the processing unit activates the stop lamp to display the first color based on information other than the comparison of the change in distance and the speed difference to the threshold criteria.