Abstract: A device for determining the distance between the rear of a trailer and a loading dock is disclosed which assists a driver backing the trailer up to the loading dock by visually and continuously letting the driver know how close the rear of the trailer is to the loading dock, thereby providing information to prevent the rear of the trailer from colliding with the loading dock. The distance between the back of the trailer and the loading dock is determined by an ultrasonic transducer which is mounted onto the side of the loading dock toward which the rear of the trailer will be backed. A display module mounted on the loading dock provides a numeric indication of the distance between the rear of the trailer and the loading dock.

Abstract: A system for preventing collisions between a vehicle and other objects, the vehicle having a blind side, an opposite driver side, a from end and an opposite rear end, has side ranging capability that determines the distance from the blind side of the vehicle to an object in a lane immediately adjacent to the blind side while the vehicle is in the process of moving into a traffic lane immediately adjacent to the blind side. Rear ranging capabilities are employed to determine the distance from the rear side to an object behind the vehicle while the vehicle is in the process of backing up. A calculating capability, responsive to the side ranging capability and the rear ranging capability, determines when an object is in a lane immediately adjacent to the blind side while the vehicle is in the process of moving into the lane immediately adjacent to the blind side and also determines when an object is behind the vehicle while the vehicle is in the process of backing up.