I'm all for forbidding touch screens for driver interaction in vehicles and I'm honestly surprised that this hasn't happened yet. Anything that takes your eyes of the road is a risk. Where I live we're pretty hard on smartphones in the car while driving (and rightly so) and yet we accept touch screens with menus four levels deep for basic stuff.
2. I don't have those numbers, in fact point of my post I'd that I don't know how we get those numbers. When I'm a passenger I'm terrified how distracted people can be by poor UI. I wish we had more hard data. Some studies are slowly emerging.