In July, Hayfield High School senior Chantelle Dobeck was returning from dinner with her boyfriend when the car was struck head-on by an apparently intoxicated driver.

Dobeck, the 17-year-old president of the Students Against Drunk Driving (SADD) council in Fairfax County, suffered injuries to her back and neck and went through seven weeks of physical therapy.

"I knew he was drunk," Dobeck, who had been a SADD member more than two years before the crash happened, said yesterday. "You could smell it from far away. It was obvious. I was very angry about it but there was nothing I could do."

Dobeck related her experience to 200 metropolitan area students on Capitol Hill yesterday at a youth conference on alcohol and driving, and left them with this warning: "Most of you think that it's never going to happen to you. Never say 'never' because the minute you say that it will happen."

Also at the conference, figures were released showing that about 16 percent of the area's 172 alcohol-related traffic deaths involved alcohol-impaired teen-age drivers -- although teens made up only 6 percent of licensed drivers in the metropolitan area in 1986 and accounted for just 5 percent of the vehicular miles traveled.

The figures come from a new study by the Washington Regional Alcohol Program, a regional coalition of businesses, government and community groups that sponsored the conference. The figures also show that alcohol-related deaths in which teen drivers were involved increased 27 percent over the previous year -- from 22 deaths in 1985 to 28 the next year.

But officials of the regional program said that the increase in such deaths does not negate the success the region has had in fighting drunk driving and that the increase may be attributed in part to improved reporting techniques and other factors.

Rep. Constance Morella (R-Md.), who followed Dobeck in speaking to the crowd at a luncheon yesteday at the Cannon House Office Building, said that no matter what the statistics say, SADD groups in local high schools are making an impression on teens who drink and drive.

"Despite the fact that you have to address the increase in fatalities," Morella said, "you, as young people, have been successful. What you do as peers is far more important than what I do as an adult. You are one of them. That makes a great deal of difference."

Beginning at 8:30 a.m., the student conferees participated in a series of workshops that delved into the subjects of peer pressure, coping with the problems of friends whose parents may be alcoholic and the importance of individual choice.

The Wheaton High School SADD group presented skits dramatizing situations involving student use of alcohol. The same students, members of a preventive substance-abuse support group, demonstrated their use of rap sessions to ease tensions that confront their peers.

The Wheaton students require that "no judging" take place in their rap sessions and other participants in the conference said that that is the concept they apply when trying to prevent their classmates from driving while drunk.

"We're not trying to push the fact that you shouldn't drink, because you're going to do it anyway," said Sean Shobe, a 15-year-old junior at Osborne High School in Manassas. "Whether or not you drink is a matter of choice but if you do, please don't drive. That's what costs lives."