The L.A. Times points out that 39 states have enacted a law of some type that prohibits drivers from sending or receiving a text or even a phone call while driving. But as the paper points out, there is no proof that these laws have reduced the number of distracted drivers on the road. One the other hand, in 2011 the number of people injured in a crash that involved a distracted driver dropped to 387,000 from 416,000 in 2010. According to the official government website distraction.gov, you're 23 times more likely to crash if you are texting while driving.
source: Distraction.gov via arstechnica