You cannot legislate common sense.

Carriers Respond To Bans On Texting While Driving -- Texting -- InformationWeek:

"Carriers Respond To Bans On Texting While Driving

The four major wireless operators agree that the practice is dangerous, but not all believe national legislation is the best way to solve the problem."
. . .
"We've got to figure out a way to stop this behavior because it's irresponsible and reckless," Taylor said of texting while driving. "You would think anyone with common sense would know that, but obviously that's not the case."