ROCKVILLE, Md. — Utah led the nation in reducing DUI-related deaths last year, even as national statistics show motorists between 21 and 34 are continuing to drink and drive more than those in any other age group.

Federal officials on Wednesday announced an ad campaign aimed at sobering up young drivers with the threat of prison and an unprecedented crackdown on drunken drivers through the Labor Day weekend.

Sgt. Ted Tingey with the Utah Highway Patrol, said the long weekend is one of two of the most popular drinking holidays, with Memorial Day being the other. The UHP, along with other state and local agencies, will begin cracking down on impaired drivers Friday with a saturation blitz. Efforts will continue through Labor Day with a few roadblock checkpoints scheduled within the next two weeks.

"We'd love to go out there and come away with nothing, but I'm sure we won't see that unless we change our habits and behaviors," Tingey said.

The National Highway Traffic Safety Administration, or NHTSA, took out radio and television ads that began airing Wednesday in English and Spanish on programs that appeal to 21- to 34-year-olds.

"People get so used to hearing it, they just don't worry about it anymore," Tingey said. The new campaign, he said will "kick it into high gear."

The cause for alarm: Nearly half the country's 11,921 motorists found last year to have a blood alcohol content of .08 or higher were between 21 and 34, NHTSA statistics show.

"That particular demographic is more at risk," said Nicole Nason, NHTSA's administrator, after announcing the campaign at a suburban Washington police academy. "They have a higher likelihood, or frequency, to drink and drive. They're also the least likely to wear their seat belts, the most likely to speed. So it's a target demographic that we really want to go after."

Coinciding with the ads, 11,000 law enforcement agencies will conduct sobriety checks and go on roving patrols until summer's end in what authorities say will be an unprecedented effort to get drunken drivers off the nation's roads.

Previous public-awareness campaigns urged people not to drink and drive and to prevent their friends from getting behind the wheel while intoxicated. But they didn't put a dent in the problem — alcohol-related traffic fatalities have remained virtually unchanged in a decade, Nason said. That's why the Bush administration decided to launch a punchier campaign, for which NHTSA has committed $11 million.