Americans are using cellphones and other gadgets behind the wheel as much as ever, despite widespread awareness of the risks involved, a federal government agency said Friday.

Citing a 2011 survey, the National Highway Traffic Safety Administration (NHTSA) said 660,000 Americans are talking or texting while driving at any given moment, a number unchanged from the previous year.

At the same time, 74 percent of American drivers support a ban on hand-held cellphone use on the road, and 94 percent favor a prohibition on texting while driving, it said, citing a 2012 survey.

Thirty-nine of the 50 states now ban text messaging behind the wheel, and 10 states forbid heldheld cellphone use -- although observers say those bans are frequently ignored.

In a statement Friday coinciding with National Distracted Driving Awareness Month, Transportation Secretary Ray LaHood called distracted driving "a serious and deadly epidemic" on US roads.

According to NHTSA data, more than 3,300 people were killed and 387,000 injured in crashes involving a distracted driver in 2011, the most recent year for which statistics were available.