About three of every 10 Metro buses last week ran too early, too late or not at all, according to a Washington Post survey of 600 bus trips in the city and suburbs.

While exploding the popular myth that Metro buses are never dependable, the survey found that on those occasions when they are not on time, the buses are more likely to be early than late.Reporters standing at bus stops throughout the area last week during morning and evening rush hours found:

In 17 percent of the cases, the buses deparated stops at least one minute earlier than the time listed on the bus schedule. The departure were at least two minutes before schedule in half of these instances.

Nearly 8 percent of the buses were more than 5 minutes late, but only a minuscule number of buses -- seven in all -- were more than 10 minutes late.

In 4 percent of the cases, the buses failed to show at all.

Early departures, even of a minute or two, can be most exasperating to bus riders who live by the printed schedule, arrive at the stop precisely on time, only to look down the street at the departing end of the coach.

Informed of the results of the spot check, Richard S. Page, Metro's general manager, said he was not upset with the overall numbers but was "distressed" by the number of early running buses."

Said Page: "That's bad for the public. We need to continuously work on our scheduling and on street supervision."

Other bus officials and riders said that the survey showed that the bus system was working unusually well and that a wait of five minutes is not at all unreasonable, considering the traffic-clogged streets of this area.

Ronald Wright, a bus rider in far Southwest Washington, expressed what was perhaps a typical reaction. "I know if I wait out here about 15 after the hour that bus is going to show up," said Wright. "It's very reliable."

Reliability was of little help to Carol Winfree, who would agree with Page's concern about street supervision. Winfree, Howard University student, stood freezing on Benning Road at 34th Street NE for 26 minutes last Wednesday morning as four buses zipped past her. The buses were reliably on schedule, but the drivers refused to stop for her because their buses were full.

The worst record was in D.C. east of the Anacostia River where the predominantly black residents have complained for years that they get inferior service. More than half the buses scheduled to pass the stop at Martin Luther King Avenue SE at Portland Street were late Wednesday morning.

By contrast, 88 percent of the buses on the same routes checked in the evening rush hours at a Southwest Washington bus stop west of the Anacostia River ran on schedule. Dozens of riders interviewed last week said this was typical.

The only perfect record found last week was turned in by the 11 buses scheduled to leave the Belair Center in Bowie. No supervisor was present the morning those buses were checked, but they all left within a minute of their scheduled departure time and none left early.

Only 11 of 26 buses listed on the Metro schedules as being equipped to lift wheelchairs onto the bus were actually fitted with wheelchair lifts.

Bus drivers are at times gregarious and like to run together, a fact that city residents across the country have complained about for years. Bus supervisors, when asked about the reason, will generally cite problems such as traffic, signal lights and varying loads at different stops. But there is no chance of buses being separated if they choose to leave a terminal at the same time.

At Chevy Chase Circle, for example, four buses scheduled to leave at 8:16, 8:17, 8:18 and 8:20, left together in a cloud of blue smoke at 8:17.

At Martin Luther King and Portland SE, an A8 bus destined for the Archives arrived 17 minutes late, accompanied by the next A8, which was running two minutes early.

At National Airport, where the subway ends and where Fairfax County residents trying to get home catch a variety of Route 11 buses, there was general discontent. Karen Palmer and Donatella Dane raced from the subway to the bus stop and attempted to persuade a lightly loaded 11F bus -- just departing -- to stop and let them aboard. It didn't stop.

Maureen Farrell of Huntington in Fairfax County said "the 11F's and 11C buses vary as much as 20 to 25 minutes on their schedules . . . . One night I worked late, knew I'd missed the last 11C or 11F, and so got off at Crystal City to catch a 9. It never came; I finally took a cab home and paid $6."

At 13th Street and Pennsylvania Avenue NW Tuesday night, a 37 bus for Friendship Heights pulled away from the stop and into the street, then was halted by a red light. A woman crossed one lane of traffic, ran to the door of the bus and knocked. The bus took off and left the woman standing.Regulations prohibit such pick-ups.

Thirty minutes later, on the same line, almost the same thing happened again. This time the door opened, the rider said thank you, the driver smiled, the light changed to green and verybody was happy, even though a rule had been broken.

At Ward Circle Tuesday morning, the 8:20 N5, a scheduled express, never showed up. At 8:32, the next N5 came along, unbelievably crowded.It only takes one miss during the rush hour to make riders unhappy.

Metro runs the fourth largest bus operation in the United States, behind New York, Chicago and Los Angeles.In September, the last month for which ridership counts are available, Metrobus carried an average of 484,000 people per weekday, including those who were using the bus to get to or from the subway. That was a 30 percent increase over September ridership a year earlier.

One evening last week at the New Carrollton Metro station, where the bus terminals can be clearly seen from the train windows as the trains pull into the station, a man ran up the escalator to catch his bus, which had left perhaps 30 seconds ahead of schedule.

"Dammit," he said to no one in particular. "Dammit. The train comes in, you can see the bus, you run, you know he's going to leave early, and he does. Every time."

The man declined to give his name. "Why me?" he asked, shrugging.