I run a Volvo 780 with a CB Antenna that reaches 13'10. I watch for the antenna to hit first, then creep. Believe me, with air freight, they send us into some wierd areas. I have been forced to a dead stop, and have called the police for help getting out of the situation I managed to put myself into. Better to look stupid then to wreck a truck. I have no problem with the dunce cap, especially if it means that I saved my truck....and reputation.