Also make sure you use the safety chains along with the wheel straps, to hold the car down.

I just made a run to New Hampshire from Michigan to pick up an Ebay car. The roads are so bad in NH and Mass. that they shook the tire belts off the wheels, twice! And I had those babies ratcheted down! Tires squashed!. The only thing that kept the car on the dolly was the safety chains. And I thought Michigan had terrible roads!!!!