Texting/talking on Cellphones while driving.

Here in Southern California I see this daily. I even see Cops doing it regularly. Technologies like handsfree and bluetooth have come along way, but are not used as much as the good ol' type in your lap or hold phone while steering with knee and eating cheesburger methods. It is illegal as far as I know but probably a pain to enforce. Should new cars come with a cellular scrambler that blocks a certain radius around cars? Or some technology that prohibits phones to work while the ignition is on? Just something I have been thinking about lately. What do you think?