So, let's say the driver measured his load at 13'7" and sees the sign read 13'9" and says "ok, I'm fine"...then, while driving through, he runs over a small imperfection in the road...WHAM, the load hits the bridge.
Your comment indicates you were unable to comprehend what I wrote. Try it again.
Only in New York State are the signs are off by a foot. The state State of New York openly admits all their bridge signs are off by a foot.
... so in your scenario, the drivers truck is 13'7" and the bridge sign reads 13'9", that means the actual clearance is 14'9".
Furthermore, the trucker doesn't have to "jam" on his brakes...what an asine thing to say
How do you figure that's an assinine thing to say? If his trailer is 13'6" high and the bridge sign reads 12'9", and he doesn't know the sign is off by a foot, are you suggesting he not jam on his brakes?
Hitting a bridge is costly. Not only can you tear up your trailer and destroy the contents of the trailer, you're company will have to pay for an inspector to check the bridge and pay for damages to the bridge.
A truck can easily cause millions of dollars worth of damage to a bridge.
I'd slam my brakes on if that's what it took to avoid going under the bridge.
I'd intentionally flip the truck over on its side or slide it down a hill into a ravine filled with rattle snakes before I ever hit a bridge.