The number of near-collisions on airport runways fell between 2000 and 2003 as air traffic declined after the 2001 terrorist attacks, according to a federal report released yesterday.

Federal Aviation Administration officials said they are "cautiously optimistic" that such incidents will not spike this year as commercial airline travel returns to record levels.

In 2003, the number of serious near-collisions totaled 32, compared with 67 in 2000. Smaller, private aircraft accounted for three-fourths of all runway incidents over the four-year period.

Baltimore-Washington International Airport had nine cases over the four years in which an aircraft was involved in a minor violation of a rule designed to prevent runway collisions or in a more serious near-collision incident. Dulles International and Reagan National airports each had four incidents during the same period. The FAA characterized two incidents at National in 2001 and one incident at BWI in 2002 as serious near-collisions.

The FAA said that commercial airlines had not been involved in any serious incidents in 2002 and 2003 in which extreme actions needed to be taken to avoid a collision. From January to July 28 this year, the agency said it also recorded no serious close calls involving commercial carriers. But at least one serious near-collision last month at Los Angeles International Airport is under review by the agency.

"This is really very good news," FAA Administrator Marion C. Blakey said. "I am cautiously optimistic" that the FAA will reach its safety goals to reduce runway incursions to no more than 27 incidents per year by 2008, she said.

The FAA said that there have been 25 serious runway near-collisions so far this year involving smaller aircraft.

Blakey and other FAA officials said it was difficult to pinpoint why the number of safety incidents had fallen, but they cited the lower volume of air traffic, better performance of pilots and air traffic controllers, new technologies and efforts to better educate private pilots who fly smaller aircraft. The FAA said it is also improving signs, markings and lighting systems on the runways to help alert pilots and airport vehicle drivers.

Officials said they are carefully tracking this year's numbers as air traffic climbed this summer to record levels at some airports such as Dulles, which is handling more takeoffs and landings of smaller commercial jets with the start of Independence Air. Congestion and weather also clogged air traffic this summer at spots such as Chicago's O'Hare International Airport, prompting FAA officials to push airlines to implement voluntary flight reductions.

Since 2000, there has been one fatal collision in which four people died at a small airport in Florida. The FAA said that the rate of runway near-collisions remained flat from 2002 to 2003 at 5.2 per 1 million takeoffs and landings.

Marion C. Blakey, head of the Federal Aviation Administration, shown Aug. 18 in Chicago with Transportation Secretary Norman Y. Mineta, said the agency has made progress in reducing near-collisions and other runway incidents.