Also: there is no way that cell phone use could be banned while in cars. This would be just as huge as trying to stop all the internet pirates. We see how well that works. Also keep in mind Speakerphone, Handsfree, Voice dialing, and systems built into many new cars.
We would all be better off having the safety issues discussed in drivers education classes & on drivers permit/license tests. What people need to learn is when, where, and how much they can be distracted without major risk. Trust me, distractions happen. It's better to educate about the topic then to enact a ban which would have little effect.