Alas for the busybodies, there isn't really all that much evidence (outside the lab) that the use of cellphones is causing calamities on our highways.
Of course there isn't, how the hell would you prove that? Ask the person after a crash if they were talking on their phone when it happened?
I've been hit by someone who I'm pretty sure was talking on a cell phone. I've seen people on phones make incredibly stupid decisions in traffic, swerve into other lanes, go 10mph below the speed limit, etc. The only other time I've seen that is when people are eating or reading (yes, reading) in the driver's seat.
So there's anecdotal evidence, lab evidence, and a good reason for not having substantial real-world data.... why do you not think that it's happening?