My Carly used to get sick just looking at a moving vehicle. She was the first dog we've ever had to get so sick.

We talked to the vet and he recommended putting her in the car and driving her to the end of the block and back once a day for several days. The next step was to drive her around the block once a day for several days. We increased the distance gradually and now don't open a car door without having a good hold on her leash. She loves riding in the car - in fact all we have to do is ask her if she wants to go "bye-bye in the car" and we get run over in her excitement.

Patience really paid off for us and I know it will for you.