These are from a NY Times piece on texting while driving. First, "The federal government estimates that at any given time about 11 percent of drivers, or about two million people, are talking on a cellphone." Their risk of crashing is about 4 times as high as non-talkers, says the National Transportation Safety Board. We don't have an official estimate of the risk being run by people who text while driving, but the NTSB thinks the risk is "much higher" than just talking on the phone.
Of course, your chance of crashing on any given day is so low that even ten times that risk is very low, so very few people will have their attitudes toward texting changed by being in an accident while texting themselves.
The other bit of government data, which I found even more interesting, is that having an adult passenger with you in the car makes your trip much safer. About 85% of drivers are alone, but when they have another adult passenger with them, their chance of crashing falls by 50%.
So let's hear it for backseat drivers....