Cadillac has a commercial out promoting its new car control technology that mimics a tablet: no buttons. I've seen similar ads for other cars too. Companies are promoting this like it's a good thing. Buttons are superior to a tablet because you can feel which ones to press without taking your eyes off the road. I realize that you can get more buttons onto a touch screen and it allows you to zoom in, but buttons are better for operation while driving.
I don't want to sound like a luddite, but sometimes the low-tech solution really is best. A touchscreen could be incorporated somewhere for something to do with cars, but reliable voice controls (initiated by a button push) would be much safer.