I will occasionally smoke in my car if I'm out at a friends who doesn't want pot in their appartment (not many friends are like that but there are a few) I just use Febreeze it works great.

As for driving while stoned. Legally it's a DUI but as we all know the legal word isn't always the best. I drive while stoned all the time I will not drive while drunk but that's because I don't feel as though my motor skills are effected enough while I'm stoned to cause me a problem while driving.