About 3:30 yesterday morning, an ambulance sped past 16-year-old Thomas M. Murphy, an Annandale youth wandering down the center of Braddock Road, trying to hitchhike home from a party.

Paramedic Richard Ray in the ambulance saw the youth "stumbling and weaving" in the street. But the ambulance did not stop or notify police. Paramedics from Burke Volunteer Fire Department, Ray explained, have been told to leave apparent drunks "to the police . . . it would clutter up the emergency radio frequency."

In the next 30 minutes, Murphy, who was only one mile from home, was probably hit by three cars before anyone called for aid, according to Fairfax County police.

The fire department ambulance that passed Murphy as it was returning to its station then was summoned to take the youth to Fairfax Hospital. He was dead on arrival.

A 30-year old Burke man, driver of the last car to run over Murphy, stopped and notified police, according to police spokesman Warren R. Carmichael.

Carmichael said yesterday that the man saw two people in separate cars near where Murphy lay on the pavement. When the Burke man told them he was calling police, they told him "they weren't sticking around for the cops," Carmichael said.

Police said tire marks on the body of the Lake Braddock High School sophomore indicate he was run over at least twice and possibly three times.

Both of the men who fled the scene, one driving a light-colored van and the other a sports car, are being sought as possible witnesses, Carmichael said. He said neither is being considered as a hit-and-run suspect.

Asked yesterday about fire department policy of ignoring apparently drunk citizens on county street, Lt. William L. Harris of the Burke fire station said paramedics "see so many people stumbling on the streets. Perhaps they don't take as much interest as they should."

Fairfax County Board Chairman John F. Herrity yesterday called for the county to make a "thorough investigation into the incident in the hope that this situation can be prevented in the future.

"Common sense should overrule procedures" in some cases, Herrity said, adding that the incident is "the worst thing I've heard of in a while."

Ray, one of the two paramedics who tried to revive Murphy, remembered that the youth had been "very hard to see" when the ambulance first drove past him. Murphy was wearing a dark denim jacket and jeans, police said.

"We didn't see him until the bright lights hit him . . . We never got a pulse when we saw him next. He was completely gone," Ray said.

John Murphy, the father of the victim, said yesterday had no comment on the accident or the county ambulance procedure.

A friend of the youth, who spent part of Wednesday evening with him said the 16-year-old had been "partying with friends" in Annandale and had said he planned to hitchhike home. The friend, who did not want to be identified, said Murphy did not appear intoxicated when he left the party.

Murphy was described yesterday by fellow Lake Braddock High students as being well-liked by teachers and students.

"He was nice, never got into trouble. He'd say hello even if he didn't really know you," said Candace McDaniel, 17, a Lake Braddock senior.

Murphy last week landed a part-time job at an auto parts store on Braddock Road, near where the accident occurred yesterday. One of the youth's teachers said yesterday that Murphy had been ecstatic about having gotten the job.

Lake Braddock Principal William H. Johnson yesterday spoke highly of Murphy, saying the youth "was the kind of teen-ager who always spoke up for his beliefs, but respectfully."

Late yesterday, Fairfax police said they had no leads in the case, and urged any witnesses to the accident to call the West Springfield Police station at 691-2702.