Yours is the voice of experience. I drive big rigs in and around the Big Apple. Plenty of surprises, even for the experienced driver.
Heading east on 495, modern highway, all the bridges at 13-6 plus. Suddenly there is a little sign on one of them: “Clearance 12-8”. Nice!
I do recall one trip where I had to deliver a load to a factory in either New Hampshire or Vermont. They manufactured desktops for school desks. This place was out in the middle of nowhere. Lo and behold, I come across a bridge w/out any height markings. I tried the CB. No one. I walked across the bridge and there on the other side, was a height marker. I had enough clearance.
I mentioned it to the folks at the factory, they said, " Oh, the sign fell off a while back, they just haven't got around to replacing it."