[goodellj]

Make sure you accurately measure your trailer yourself. While you are at it, measure your truck and trailer, heights, widths, and lengths, and make a note and post it on the dash for quick reference. Check out the Wikipedia article on "Interstate Highway standards" and read the section on vertical clearance. The standard height of semi-trailers is 13'6", so I feel more comfortable on roads with truck traffic. I would never go under a bridge with only 1" of extra clearance. My Montana is 13"4" and I won't go under a bridge unless tractor trailers can use it.