The difference in height between the dock and the truck bed. Most trailers feature a 55" truck bed height. Refrigerated trailers are usually 59".
Width
The dock board width should exceed the overall width of the pallet or vehicle used by at least 12-18". Wider boards allow for improved mobility and efficiency.
Capacity
Dock Plate: The capacity must exceed the combined weight of the heaviest load and the vehicle's weight.
Dock Board: Three times the vehicle lifting capacity. More for three-wheeled forklifts.