Maximum legal truck height here in CA is 14 feet. All overhead obstructions must be labeled as to what the maximum height is, and it is accurate to the lowest point on the bridge. They have Road Atlases that list the height and maximum load capacity of every bridge in the USA, and truckers are required to heed them (I did drive a commercial truck many years ago and this was the law). I can see a guy in an RV, and maybe a guy in a rental truck, but there is no excuse for the commercially licensed drivers to make that mistake.
Makes for a good comedy though!