Originally Posted by captainoftrasea
We have a maximum height of 16 feet on side roads most motorways are 18 feet but always check and we did a dry run with a laser measure to be safe.
I was trying to find a map of bridge road heights but I have failed so far even though I have seen this map. I did find that the US Interstate system has a design requirement that an Interstate has at least ONE path that is not restricted by a height of less than 16.5 feet. Overpasses have to be at that height OR easy on/off ramps have to be available.
Now the interesting tid bit was WHY 16.5 feet?
Apparently the US had an atomic cannon that required this height to be transported on the US Interstate system.
The cannon is long gone but the requirement remains.