The importance of knowing how tall your rig really is

i used to haul boats all over the country. Sometimes i would have to pull to the side and let a little air out drive under and air back up. it was that or go around 100 miles. once i took a steering wheel and throttles off because over some bad info. Any rig over 13' 6" is to high. you are then responsible for any damage to overhead wires, street lights, etc. the cables do stretch on hot days.