DAYTONA BEACH, Fla. -- In the good ol' days at the Daytona 500, a security guard would poke through Dave Roberts' motor home, checking to see if he was trying to sneak friends into the race.

Now, the guard comes through with a dog -- searching for bombs.

Indeed, America's heightened security is having an impact in even the most carefree of environments: the beer-swilling, fun-loving home of debauchery known as the Daytona infield.

With the nation on high alert for terrorism this President's Day weekend, officials at Daytona International Speedway took extra precautions to protect their packed crowd of an estimated 200,000 for Sunday's big race.

An estimated 200,000 watched Michael Waltrip win the rain-shortened race Sunday. No major security problems were reported.

"I had friends who told me not to come here,'' said Roberts' wife, Denise. "I told them I had to. If they let us change our lifestyle, then they've won.''

So, the party carried on, albeit with more than a few eerie reminders of the realities.

Bomb-sniffing dogs checked motor homes. Hundreds of policemen and yellow-shirted security staffers used mirrors to check under cars for explosives. Early Sunday, one security guard said he had confiscated a few dozen fireworks but nothing more sinister.

Once inside the track, Roberts and hundreds of others living in the makeshift tent cities saw police circling their living quarters every few minutes.

Although Army Blackhawk helicopters flew over the track repeatedly in the days leading up to the race -- "They woke me up three times last night,'' Roberts said -- officials insisted they were merely rehearsing for a flyover as part of prerace pageantry.

There wasn't much else flying overhead. The Federal Aviation Administration restricted noncommercial aircraft within three miles around and 3,000 feet above the track. That grounded the banner-toting ad planes that normally depend on this weekend for revenue.

"I understand national security, and am 100 percent for President Bush, but they keep picking on us,'' said Tim Pacini, of Aerial Messages in Flagler County.

Of course, not every system is foolproof, and fan Doug Scott said nobody inspected the SUV that he and his girlfriend slept in this week.

Still, track officials were guaranteeing a thorough security sweep. People noticed.

"I've never seen such tight security in a big arena like this,'' said Daytona 500 grand marshal John Travolta, who went to the Super Bowl and World Series in the past year. "I don't think I'd bring my family here if it wasn't safe.''

In the grandstands, where about 135,000 of the fans were set to watch the race, only soft-sided coolers big enough for about a six-pack were allowed. NASCAR handed out clear, plastic bags to store souvenirs. Fans weren't allowed to use carrying cases for their race scanners and binoculars.

Cynics said the limit on the size of coolers was a ploy for NASCAR to make more money at concession stands. Track officials said security was the No. 1 priority.

"We view it as a safety measure only,'' track spokesman Glyn Johnston said.

NASCAR crowds traditionally are white and Southern, and many fans expressed the belief that a foreign terrorist might have a tough time blending in.

"I thought about not coming for a while, because in a time like this, the three places you don't want to be are the Super Bowl, the Daytona 500 and the Kentucky Derby,'' Scott said. "But then I heard they were beefing up security, and I changed my mind. They've made me feel safe.''