Height clearances of overpasses and bridges

..and another thought..we've been full-timing for 16+ years and our preferred way of traveling is off the interstates and we have a 40' motorhome. We've gone to Alaska, also. We choose public campgrounds - national forests, etc. We have never 'checked' the overpasses by various means and don't use a trucker's atlas. However, we don't get into big cities (the interstates going through them are all o.k. - truckers do them all the time), but we don't get off on a small city street and wander through town. I think if you use common sense you'll really be o.k. Just think how all the delivery trucks delivery their goods to places. Good travels!!