What is a bridge plate? Each truck is assigned a number that roughly translates into tons fully loaded. When crossing a military bridge, Bailey for example, the bridge will have a number posted on the approach to the bridge. If the truck's number is higher than the bridge, you are too heavy and will be turned away. You see these posted all over Europe even on regular roads. The letter "C" on the upper crescent of the plate indicates combination weight, like a tractor- trailer. There was an article in "Military Vehicles" several years ago that discussed this and listed the trucks and what number should be posted on the bridge plate. Cool military item anyway.