Priority 1: Drive the car.
Priority 2: Navigate, where #1 can be achieved.
Priority 3: Anything else that doesn't interfere with the other two.
I was going to write a longer comment, but then I decided I'll just summarize:
Drive the damn car; if you play video games while attempting to operate a car, you're a fucking imbecile.
If people would take more concern with how their actions *might* affect others, the desire for the nanny-state might actually be lessened.