Abstract: A computer controlled signalling system to assist a driver in accurately positioning a truck chassis at a preprogrammed specific stop point in a loading/unloading lane adjacent to a dockside container crane to facilitate loading/unloading of containerized cargo by the crane and employing a light signal panel visible to the truck driver and having a series of vertically disposed lights thereon sequentially actuated by a computer. The vertical lights indicate to the driver the exact distance he is from, and when he reaches, the desired stop point. The computer is responsive to a video image received from a video camera disposed over the traffic lane and matches the image(s) received with a programmed image for locating, identifying and signalling the position of the truck.