ATLANTA: More than half of U.S. students in their last year before college admit they text or email while driving the first federal statistics on how common the dangerous habit is in teens.

An anonymous national survey conducted last year found that 58 per cent of students said they had texted or emailed while driving during the previous month.

The Centers for Disease Control and Prevention released the survey results Thursday.

The numbers aren't really surprising, said Amanda Lenhart, a senior researcher at the Pew Research Center in Washington. She studies how teens use technology.

A typical teen sends and receives about 100 text messages a day, she said. ''A lot of teens say, 'Well, if the car's not moving and I'm at a stoplight or I'm stuck in traffic, that's OK,''' said Lenhart, who has done focus groups with teens on the topic.

Other teens acknowledge they know it's not safe, but they think it is safer if they hold the phone up so they can see the road and text at the same time, she said.

The CDC survey didn't ask whether students' texting was done while the vehicle was moving or stopped.

Transportation Secretary Ray LaHood on Thursday pressed states to ban texting and hand-held cellphone use by all drivers, calling the problem ''a national epidemic.''

LaHood said he wants automakers to back voluntary government guidelines to ensure dashboard technologies won't distract drivers.