Every state has its own laws for “overhauling cargo” (cargo that sticks out beyond the dimensions of the vehicle). However, the Federal Size Regulation law from the U.S. Department of Transportation states that cargo can overhang a vehicle by: - 4 feet in the rear - 3 feet in the front - 4 feet on the sides As long as your kayak doesn’t exceed that limit, you should have no problem hauling it in the back of your truck. If it does exceed the 4-foot-in-the-rear limit, consider using a truck bed or truck hitch rack.