I think that the best idea in this sub-thread is that in a post by funwithBSD, an immobilizer.(Presumably similar to a breathalyzer. If you are convicted of texting-while-driving you must put a device in your car that will disable the car/cell phone of the car occupant. A cell phoen app won't do the trick, but maybe a car-based device would.)
I guess your post and my post prove how typically polarizing these cell phone issues are. I am not a nanny state fan, but I am infuriated by how stupid and inattentive people are hurting others and the toothless laws that currently exist. I don't have a cell phone glued to my ear and would rather not be wacked in traffic by someone who does. Other people see it differently, and flip if they can't use their cell phone everywhere all the time.
The same issue comes up if a private party wants to block cell phones in their movie theater, for the benefit of other patrons. Half the of everyone loves the idea, the other half hate it.
I am shocked at the scope of the distracted driving problem and that nothing effective is being done to deter and punish violators. And I'm concerned that the problem will probably get worse.