Cellphones and Driving

Alberta is considering following several other provinces (NS, ON, QC) in banning the use of cellphones while driving. I personally think its a good idea, but my experience involves seeing several friends have accidents while on their phones.

I'm curious as to how such a change in legislation will affect accidents via changes in behavior. With respect to seat belts, some have argued that the reduction in risk presented by a seat belt is compensated for by increases in speed and other increases in risky driving behavior (something called risk compensation). I came up with a couple of (back of the envelope) competing hypotheses on the cellphone ban:

1. Banning cellphone use may result in people paying closer attention to their driving, thereby reducing accidents.
2. Banning cellphone may result in people increasing their speed, perhaps driving more recklessly in order to get home or to the office to make their calls.

Any other hypotheses are welcomed. Once I have enough hypotheses, I'll look into setting up a track and renting some go-karts.