Metrobus, which carries 500,000 passengers a day across the region, is a dilapidated system that suffers from weak supervision, old equipment and buses that travel in bunches, wrecking schedules and service, a panel of bus experts told Metro directors yesterday.

"You need to invest in your bus service," said Michael Scanlon, who led the panel of managers from bus systems in Houston, California, Toronto and New York. Scanlon runs the San Mateo County Transit District in California. "You have a case of a rubber band stretched too far and about to snap in some cases."

Metro Chief Executive Richard A. White had asked the panel, organized by the American Public Transportation Association, to review Metrobus operations. Another association panel examined Metrorail earlier this year, also at White's request, and recommended ways to improve rail service.

The bus panel found room for improvement in the equipment, operations, driver training and maintenance of Metro's 1,460 bus fleet.

White agreed with the panel's findings and said that while Metrorail has gotten attention and dollars, the bus system has languished. "It has really taken a back seat," he said.

Part of the problem is that several suburbs that help pay for Metro service also operate their own bus systems, and their allegiance -- and financial support -- is divided, said D.C. Council member Jim Graham (D-Ward 1), who represents the District on the Metro board of directors. "We don't have a unified approach for bus, as we do for rail," he said.

The average age of a Metrobus is 9.9 years, twice what it should be, Scanlon said. "Many are over 15 years old," he said. "Anyone who owns an automobile knows that the older it is, the more maintenance you have to do, the less reliable it is."

Metro directors yesterday approved a $1.5 billion capital and operating budget, but a small portion will be spent on the bus system. Metro's capital plan calls for the purchase of nearly 900 new buses over the next five years, which will reduce the average age of a Metrobus to 7.5 years. But that still exceeds the level recommended by the panel.

Some mechanical breakdowns could be avoided if drivers properly inspected the buses before they begin their routes, as required by federal law, Scanlon said. "It will help you before you get a piece of equipment out on the road that then becomes a road call," he told Metro officials. "Your own audits and our observations show your operators are not doing it."

Metro managers said they have begun to require operators to perform the inspections and about 70 percent are complying.

The panel also found that bus service could run more smoothly with better supervision. Metrobus routes are plagued by "bunching," in which several buses on a route travel in a pack, Scanlon said. Bunching often occurs if traffic or some other problem causes the first bus to slow down and the following buses to catch up.

Bunching throws off the route's schedule and the distribution of passengers. Often, the first bus becomes crowded, while the last bus in the bunch carries few passengers. Supervisors posted on streets along a route can eliminate bunching by directing the second or third bus in a row to skip a stop and head to the next one.

But Metrobus has no real street supervision, particularly at night, Scanlon said. "You've got, like, one guy, running around," he told the board. "It's great to trust the employees, but if you're going to control the quality, particularly on the off hours, you need good street supervisors."

Metro employs 73 street supervisors and has 10 vacancies for the job, said Jack Requa, Metro's chief operating officer for buses.

The supervisors are supposed to monitor 350 routes and are stretched too thin, said Jim Hughes, Metro's acting deputy general manager for operations.

Metro should make a better effort to view bus service from a passenger's perspective, Scanlon said. The agency should start evaluating performance by regularly tracking the number of buses that start routes on time and adhere to schedules and that experience breakdowns that prevent them from completing routes.

Metro has failed to examine bus routes regularly to make sure they meet demand, Scanlon said. Bus managers haven't ridden some routes in three years when they ought to be monitoring them three times a year, he said. "What's happening on the street? You need to check that demand is being met. That's where the action is -- on the street. Not in our offices and not even in the bus garages."

Service is hampered by the bus system's high vacancy rate, which causes excessive overtime and absenteeism, Scanlon said. The department is supposed to employ 2,400 bus operators but has 122 openings. It is budgeted for 800 mechanics but is short by 59, Requa said.

One factor that might be feeding the labor problem is Metro's policy that all bus operators start as part-time employees, Scanlon said. Metro created the requirement several years ago, saying it would reduce costs. But it is hurting Metro's ability to attract good workers, Scanlon said. "There are a lot of good candidates who would not be able to put themselves in a part-time situation because of the economic realities," he said.

The panel also found that bus garages are cramped and poorly lighted and ventilated, making it difficult for mechanics who repair and maintain Metrobuses to work efficiently.

Scanlon had good words for the men and women who drive the buses and those who maintain them. "You're very, very fortunate," he told Metro directors. "People work very, very hard each and every day. . . . But I think you have to give them more tools with which to work."

A Metrobus continues past a stop on Arlington Boulevard at South Glebe Road in Arlington. A panel reviewing Metrobus has suggested cutting stops.Board member Jim Graham says support is disjoined.