From an NPR piece headlined "Experts Question Need for Stronger Cellphone Ban":
states with cellphone bans have seen no real decrease in accident rates.
"The curious thing is that even as cellphone use has increased exponentially by drivers in vehicles, we see no surge in crashes," Rader says. "So as this trend has accelerated, with more and more people having phones in their cars and using them, the number of overall crashes has been declining."
The host on WBGO-FM this morning suggested a ban on eyeliner application while driving.
The comments string on the earlier post here on this topic gets into the issue further.