Overpass Minimum Height

13'6" is the legal height. you would be very wise to accurately measure the height of your rig!

Over passes less then 16 feet must be marked for actual clearance. Some structures are arched, the lowest point, normally at the fog line, under 16 feet will be marked there.

The "or so", will get you some day. Hook up and measure for piece of mind

Measure to be sure of your exact travelling height. If your height is close to the posted clearance, use caution. That sign may not be accurate. I remember one instance years ago that a 13'0" truck got stuck under a bridge posted as 13'5". years of road repairs and resurfacing added an extra 6 inches of asphalt to the road surface. The clearance sign was never changed until after they removed the truck and remeasured. and another instance but the reverse. Sign says low clearance 13'6" in right lane. The bridge was completely replaced about 2 years ago with a new structure with about 16' of more of clearance. The sign is still there.
If in doubt, check it visually.

Ken

I seriously doubt you'll be taller than my 40' toy hauler, which is almost as tall as an 18 wheeler's trailer, and I've had no issues clearing interstate highway bridges or those on state routes. When I'm in doubt I consult the Motor Carrier's Atlas that displays routes approved for 18 wheelers. If they can make it so can I. If the bridge is marked under 13' I go another way. I've been lucky and have yet to be turned around.

Put a level on it and a tape measure to the ground then put a sticker on your dash board.

50 mph isn't when you want your mind racing to remember what the height is. I'm 12'10" and been under a couple of them that where less than 13'6".

I pulled into an older gas station in a pinch that wasn't posted and looked low. As I pulled in I kept going up the ladder to look and the gal came out and said yes its low, another guy busted out a row of lights the other day. I wasn't double towing at the time and backed out.

As far as bridges etc, buy the motor carriers road atlas. Since I'm double towing and diesel I try to always go to truck stops.
Google Earth/street view is very handy for planning.

This is no rule but the newer places along the main routes seem to all be fine. The low places I've run into were older more rural and old rail under passes. Its reassuring to see semi trucks on your route.

I’m 11’4”, as I am sure the rest of us are, give or take. When I am towing I have that dimension on a sticky taped to my dashboard to remind me just in case I approach a low slung looking bridge. You never know when it might come in handy.

If you are travelling to Canada anytime, write down the metric conversion height as well.

Watch side roads and highways. We were in the south and there was a RR bridge that was 10' my bold gamin sent me there. Was saved by the guy in a corner house that came yelling at me as I turned. I was able to back up and go another way.

Used to travel on business to this area in S Carolina and saw a couple of accidents on thus bridge


https://youtu.be/USu8vT_tfdw

Never know when you might come across this situation...when Mr Murphy stikes...