This SAE Information Report will provide a uniform arrangement with which to evaluate the concept of high-mounted lamps on large vehicles. The report provides test procedures, requirements, and guidelines for high-mounted stop lamps intended for use on certain vehicles 2032 mm (80 in) or more in overall width.
This information report applies to trucks, motor coaches, closed and open top van trailers and other vehicles with permanent structures greater than 2.8 m high. They are not intended for use on school busses, truck tractors, flat bed, pole, and boat trailers and all other trailers or trucks/truck bodies whose permanent structures are less than 2.8 m (approximately 112 in) high. These lamps are for the purpose of providing a signal over intervening vehicles to following drivers.
Additionally, four widely spaced lamps will make a more conspicuous stop lamp pattern, thus making it easier to identify a large vehicle as slowing or stopping when approaching it from the rear.