Personally i'd ban the use of cellphones while the car is in motion. Most of them now have accelerometers. Use it. Disable the phone if the car is moving. Less distracted morons on the road is good for everyone. Oh you're a passenger? We'll have passenger mode. Get caught driving with your phone in passenger mode? $10,000 fine and a month in jail. We'll put a stop to driving while distracted real quick. At least for phones. Is it perfect? Nope. But it's a good start.
Why do you include all the accelerometer/disabling/passenger mode steps and not just skip to "Get caught driving with your phone? Huge fine & jail time."? It would require a lot less hurdles.
Personally, I'd prefer taking the device out of the equation, and just stick to "Driving badly? Heavy consequences." Much simpler.