I realize that you are not proposing (at least yet) blocking cell phones while driving, but if you decide to, count me in as a HUGE supporter! I have used cell phones for 23+ years. Sadly, every day I see more and more cases of distracted drivers and in nearly every case, they are holding and using handheld cell phone. Outside of dialing 911, I see no valid reason for drivers to talk and drive. You may be interested in a recent study that my company did on this topic. http://powerfeedback.tumblr.com/post/1609603005/dying-to-drive