minimum clearance

Them and auto haulers, too. Happens all the time. Makes life interesting for heavy haul drivers and others who have low clearance trailers. The name of the game is to keep the load as low as possible to get under as many bridges as possible, and deal with the higher grade crossings and other such issues when they come up.

 

I can speak for lowboys, but my car trailer is 2 1/2" from the road surface along its belly and 4" at the tail. I try to avoid it, but it does scrape on some driveway entrances and crowns in the road, and I will admit I did get it hung up on a raised manhole cover one time hidden by some tall grass on the side of a state highway. Not fun, but you learn to deal with it and be aware of your situation.