There has been a lot of discussion in the past on this. If you wish to travel and not take the chance that your vacation is interupted, there are online permit services that can arrange them for a fee. Check out www.comdata.com and www.tel-trans.com. If you want to make the arrangements yourself, the later site has a listing of all the state's DOT websites. I'd guess you could contact them individually and make your own reservations and save the service fees.