A review of recent scientific studies on the issue of distracted driving published in today's New York Times: http://www.nytimes.com/2009/07/28/technology/28texting.html. See here for more, and here for NYT's "Driven to Distraction" article series.
About half of drivers 16 to 24 said they had texted while driving, compared with 22 percent of drivers 35 to 44.
“It’s convenient,” said Robert Smith, 22, a recent college graduate in Windham, Me., who says he regularly texts and drives even though he recognizes that it is a serious risk. He would rather text, he said, than take time on a phone call. “I put the phone on top of the steering wheel and text with both thumbs,” he said, adding that he often has exchanges of 10 messages or more. Sometimes, “I’ll look up and realize there’s a car sitting there and swerve around it.”