I have to deal with a small bridge on a little traveled county road. The bridge is rated for 4 tons, wide enough for 1 car in either direction and has no siderails. It really is rediculous. My Ford F250 weighs more than 4 tons. Am I liable if the bridge collapes when I cross it in my unloaded pickup? I have even requested that the county just remove the bridge and put a slope with a cement bottom in the ditch which is dry unless is rains. They don't want to do that either. I am one of the few people who use the road. When I drive tractors/equipment on the road, I go through my adjacent field, down through the ditch (which isn't very deep and next to the bridge) and back onto the road.
The guy driving the tractor was just plain stupid. The tractor alone weighs more than nine tons. My guess is he may have crossed it empty before but forgot the trailer was loaded.