Just use SetCharacterView() when your char represents a car and ChangeCharacterView() when he is a human.
player has chosen/changed his character:
player has got in a car (set temp view):
player has get out of a car:
Also when the player picks up a char you can use a global int to store it's current state (car, bussinessman, bikergirl, etc). Then you could check it later whenever you need.