PITTSBURGH (AP) _ What started out to be a routine traffic stop for speeding turned into brush with death for an Arizona policeman, who was saved by a passerby.

As Russell E. Dean tried to arrest the 16-year-old driver, the boy knocked the Phoenix officer to the ground, grabbed his gun and threatened to kill him. Dean believes his life was spared only by the bravery of the motorist who stopped his own car, grabbed the boy and pulled him from the policeman.

The passer-by, John W. Basey, 40, a window washer from Phoenix, was among 20 people honored by the Pittsburgh-based Carnegie Hero Fund Commission for risking their lives trying to save others.

''Mr. Basey walked right up in the face of that gun that could have gone off at any time,'' Dean said. ''I believe Mr. Basey saved my life.''

Those honored Wednesday bring to 111 the number recognized this year. The organization has honored 7,405 North Americans since industrialist Andrew Carnegie established the commission in 1904.

Each hero or survivor receives a $2,500 cash reward and medal.

Dean said he almost quit pursuing the youth he was chasing on July 19. The youth reached speeds of 80 mph on Phoenix's streets before crashing his car into a tree.

When Dean stopped to apprehend the boy, the teen-ager turned on the motorcycle officer and fell on him. The boy pulled Dean's .38-caliber pistol from his holster and pointed it at his head.

''He put the gun right to my left eye and he said he was going to kill me,'' Dean said.

As Basey talked the 16-year-old into releasing the gun, Dean handcuffed him. Dean suffered only a sprained knee and scrapes to his arms and legs.

The other heroes cited:

-Derek Lambert, 16, of Andrews, S.C., who saved a man who had fallen from a boat and severely cut his hands on the propeller on Oct. 9, 1988.

-Milton E. Bradford, 32, of Newport, N.J., who died saving a co-worker who was overcome by gas in a sewer shaft on Sept. 6, 1988.

-Shirley Belle Viscusi, 58, Howick, Quebec, a nurse who died trying to save a woman who suffocated in a home for the elderly that had caught fire on July, 25, 1988.

-Michael B. LaRiviere, 18, Rockaway, Ore., who died while swimming to save a man caught in an ocean current on July 30.

-Martin A. Benfield, 27, Lenoir, N.C., who nearly drowned pulling two young boys out of the ocean June 14, 1988.

-Leonard A. Theroux, 65, Chepachet, R.I., who pulled a trapped man from his burning auto before the vehicle became engulfed in flames on Feb. 18.

-Aaron Lorne Clark, 25, Magdalen Islands, Quebec, who drowned while helping to save a 13-year-old girl in the Gulf of St. Lawrence on Aug. 21, 1986.

-Jerry L. Conrad, 35, Toledo, Ohio, who leaped into a moving car to save a 2-year-old girl on Sept. 23, 1987.

-Jerry O. Anderson, 35, Tulsa, Okla., who drowned while saving a 12-year- old boy who had fallen from a dam into deep water on May 27.

-Allen N. Davidson, 13, Gaffney, S.C., who crawled into a burning house and dragged an elderly woman to safety on Nov. 19, 1988.

-Michael Ollins, 33, Chicago, a bus driver who left his vehicle and stopped a group of young men from beating a man on a crowded city street on Aug. 20, 1987.

-Claude Cleroux, 50, Montreal; Serge Perron, 38, of Repentigny, Quebec; and Robert K. Myles, 37, of St. Hillaire, Quebec, all of whom helped save a co- worker trapped beneath a crumbling wall after an explosion in an oil refinery on December 16, 1986.

-Scott Walter Asson, 20, Burley, Idaho, who broke the window of a car and pulled a woman free just before the auto was submerged in a flooded wash in Scottsdale, Ariz., on Oct. 14, 1988.

-Donat Pelletier, 43, and Guy Bernier, 41, both of Ste. Felicite, Quebec; and Denis Blanchet, 42, and Rejean Miville, 35, both of St. Pamphile, Quebec, who crossed the partially frozen surface of the St. John River to rescue a co- worker trapped in a bridge that was carried downstream April 1, 1986.