I used to work for my local Utility company and in all of our Line trucks big and small (think F350/450 Chassis) and all dump trucks have a sign on the dash stating the height of the truck. Not that we have any low bridges around but its a great reminder. However the city of Champaign IL 20 miles south of me has a couple of LOW bridges that get hit routinely YES the bridges are MARKED with Hi-Vis Yellow paint and Flashing lights and signs leading up to the bridges yet Drivers hit them regularly. Maybe if the signs read WARNING CAN OPENER AHEAD Maybe the truck drivers would realize that the bridge is LOW LOL. The bridges do a number peeling back the roofs of trailers :B As for my TT I have a sticker on my dash reminding me and fortunately I haven't found low bridges while traveling yet.