Release an aftermarket iOS/Android car dock that will bluetooth sync to the phone, and give the user a slap on the wrist if the phone is not docked when moving, or otherwise in use, and invoke a reward system from the parents/insuance/what have you for not using the phone while you are driving the car. If a sibling is involved or the car is shared with multiple drivers, one phone being synced would be sufficent to deactivate the nanny device, but it could keep an eye out of the other users phones it is synced to, depending on the owners leisure, and who is driving when.