Towing a full profile fifth?

At 13'5" we've not had any issues. Even low train overpasses in two small towns (one in North Carolina, one in New York) that were labelled 13'6" were plenty tall. The posted clearances are the minimum clearances and the rest of the overpass tends to be higher. A standard 53' semi-trailer is 13'6" to 14' tall, so I do four things while driving: 1) use an RV GPS with my rig parameters in it; 2) watch the clearance signage like a hawk; 3) watch for tractor trailers - both in front of me and coming the other way (if they can do it, I can, too); and 4) move to the inside lane for arched tunnels and overpasses. One caveat to keep in mind is that clearance signs aren't always changed after roads are resurfaced (often laying new asphalt over an existing repaired road surface which can raise the road level several inches).

Rob