Officer Seth Weinstein is the "DWI King." Ever since he joined the Alexandria Police Department five years ago, he has made more than 100 drunken driving arrests annually -- between a quarter and a third of all such arrests made in the city each year.

Weinstein, 37, gained a certain fame as the officer who arrested Alexandria School Superintendent Rebecca L. Perry in April on a charge of driving while intoxicated. She pleaded guilty and has continued in her job, although controversy over the incident has not gone away.

Weinstein's colleagues say his record is impressive. Many of them make two or three arrests each month. Two years ago, Weinstein managed three in a single, very busy night.

"Most people I arrest are not bad people. They just made a mistake," Weinstein said as he cruised along Route 1 in the early hours of a recent Sunday morning, searching for erratic driving. "My job is to document that mistake."

Each year, drunk drivers kill about 50 people in Northern Virginia and more than 350 in the state, according to the Virginia Department of Motor Vehicles.

Historically, drunken driving is particularly deadly on Labor Day weekend. Nationwide, nearly 56 percent of all traffic fatalities during the holiday weekend in 2002 were alcohol-related, according to the most recent statistics from the National Highway Traffic Safety Administration. In the Washington area, 28 percent of traffic deaths throughout the year were related to drunken driving. The national figure for 2002 was 41 percent.

Weinstein's colleagues say they can't explain why he is so effective at arresting drunken drivers. Some wonder whether a well-concealed, personal tragedy fuels his tenacity. But he says that's not the case. He's just doing his job, he says.

Stopping someone on suspicion of drunken driving can spark a contentious situation.

"The law's very complicated, and a lot of people fight these things," said Officer Gavin Hillard, whose arrest tally usually comes in second to Weinstein's. "Everyone really values their driving privileges."

An arrest can be difficult and even messy, officers say. Some handcuffed suspects have vomited on officers and in their cruisers.

For those arrested on a drunken driving charge in Virginia, the stakes got even higher July 1, when 25 drunken driving laws took effect, making the state one of the nation's toughest on intoxicated motorists. Those charged with having a blood alcohol level of 0.15 or higher face at least five days in jail and would be required to use a dashboard breathalyzer for six months. The device prevents drivers from starting their cars if their blood alcohol level is 0.08 or more, the legal limit in Virginia.

Weinstein talked about the people he arrests, referring to them as "stupid" and, sarcastically, "really smart." Their excuses never work, he said, because he usually can smell the alcohol on them, regardless of what they do to hide it. One "smart" guy tried to mask the odor by spritzing cologne in the car.

"You could see the mist," Weinstein said.

Weinstein said he is careful about his own use of alcohol. At home with his wife, Weinstein said he has an occasional beer or glass of wine at dinner, but he does not drink outside the house. "My personal standard is much [higher] than the legal one," he said. "If I feel even the slightest bit under the influence, I won't drive."

The department's breathalyzer sits in its own room, called the "intox room." It looks like a cash register without the drawer.

On a recent early morning, Weinstein gave a breathalyzer test to a man another officer had brought in. He was polite and professional -- almost fatherly -- when he got down to the business of measuring blood alcohol levels. He explained what was happening, giving tips: Wait 20 minutes after any burping or throwing up before taking the test, because such activities may increase blood alcohol readings. If a person's hands have alcohol on them, putting them in their mouth also might raise the reading, he said.

"Blow on it for 10 seconds like a balloon," Weinstein said, referring a man to a clear mouthpiece attached to a warmed, flutelike pipe that receives the breath sample. "You're going to wait two minutes and do it again. You did a good job." The reading: 0.08.

Weinstein then headed out for another lap in his cruiser. Minutes later, he arrested a 22-year-old enlisted man who was speeding in his 2003 Dodge Neon down North Henry Street. Once out of his car, the man failed the field breathalyzer test and three other tests for drunkenness that Weinstein administered curbside.

"Officer, please, dude, I am desperate, sir," the man pleaded through the plexiglass shield after Weinstein tucked him into his cruiser.

The heavy, 6-foot-2 driver told Weinstein that he had had only two beers.

"Everybody has 'two' beers. That's what everybody [in Virginia] says," Weinstein said. "In North Carolina, it was three." He was an officer in Raleigh for five years before moving to Alexandria.

After the curbside breathalyzer test registers 0.09, the driver said he had had four beers. Weinstein, who has tested the machines he uses, said he has to drink at least six beers to blow a 0.09.

"There's no point in lying anymore, because I'm not going to buy it. The machine's not going to lie for them either," he said.

Alexandria police Officer Seth Weinstein, right, with Officer Barry McManus, makes an early morning arrest recently after a field sobriety test in Old Town Alexandria.Seth Weinstein gives a field sobriety test to a driver. He says most of the motorists he arrests aren't bad people, but have "just made a mistake."

Weinstein, with a driver whose blood alcohol content registered 0.14, tests his breathalyzers himself.