Bridge Clearance for Semi-Trailers? - Model Railroader Magazine

There are some federal rules about signing low bridges, but it boils down to this:

If it's a truck route, statutory clearance is 13-6".  Some states have statutory clearance of 14'.  All truck routes have bridges lower than this MUST post the bridge, and should have (if not must have) sign in advance of the bridge, say at least 1/2 mile to 1 mile.  If the road is truck restricted or truck prohibitied, then advance warning signs are not needed, but the bridge should still be posted for the joker who tries to take a rental truck through.

Many trucks have hit bridges, sometimes the state or county ends up paying for the damages if the trucker can prove the bridge was not properly marked, and the road was not truck restricted.

In HO scale, 13-6" comes out to 1.86" or so, 14' comes out to 1.93".  I would allow 2" for road clearance, this would equal 14-6".

Brad

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