Hmmm, interesting....
I once worked with a gal who had been in an auto accident and had to have neck surgery, she was making a left hand turn and was hit. She wouldn't make left hand turns, for years! Eventually she got better.
As "NASCAR" Nancy I would suggest Richard Petty's driving school, but that wouldn't be right.
But hey, maybe a hot lap around the track might do it.
OK, serioulsy, I guess I would have to ask exactally what is the phobia? Freeways, speed, others driving around you, being in the car itself a small space?