Thousands of Washington area commuters spurned their fuel-starved autos for public transportation yesterday, swamping Metro's bus and subway system in near record numbers and severely straining the transportation network.

Metro officials, scrambling to deal with overloaded subway cars, balky farecard machines and crowded buses, broadcast pleas for prospective riders to avoid rush-hour travel if possible.

Two weeks into the area's gasoline shortage, an estimated 40,000 new riders have turned up on the subway system alone - a daily increase of more than 15 percent. New riders jamming the buses still are uncounted.

Meanwhile, the D.C. Public Service Commission, acting after scattered threats of a city-wide taxi strike, boosted cab fares by 10 cents per person per trip beginning Sunday. Cab drivers, supported by D.C. Mayor Marion Barry, demanded still higher rates to help pay for time and money lost to gas lines and higher fuel costs.

During peak rush hours yesterday, large crowds thronged bus stops and subway stations. Buses on some routes were 10 to 45 minutes late as drivers maneuvered around and through lines at the few gasoline stations still open. Some subway trains were 10 or more minutes late amid what Metro transportation officials called "usual mechanical breakdowns."

"The types of [mechanical] problems we had today are not uncommon, they happen every day on the subway lines," said Metro spokesman Cody Pfanstiehl. "But when you have many more people riding than usual, the problem [of moving people quickly] is multiplied - it's a rippling effect."

The numbers of people riding both bus and subway has increased steadily since the two-week-old gasoline crunch began in the area, officials said, but leaped dramatically last week.

On May 28, 262,285 people rode the subway. The same day one week later, the number rose slightly to 262,600 and then rocketed last Friday to record 301,398.

Yesterday's total was down about 15,000 from Friday but appeared to be bunched more during rush hours. Regular commuters reported buses, trains and platforms unusually crowded. Bus drivers said many of the riders obviously were new, asking questions about routes and fares.

Pfanstiehl said Friday's crowds were less visible because minor foulups - stalled trains, sticking escalators - did not occur during rush hours as they did yesterday.

"Every bus that goes out of here [now] is a lot more crowded," said a bus drivers yesterday on the J2 route into Friendship Heights. "This line has picked up tremendously since this gas thing started. I had to turn people away for the first time - and the bus behind me and the bus behind that one, too."

Metro bus supervisor Bennett Dancy counted 24 buses yesterday with standing room only in Silver Spring. He estimated that as many as 25 percent of yesterday's rush hour passengers were new riders.

"The ridership jumped at such a rapid pace that no system could keep up," Dancy said.

Pfanstiehl said Metro cannot put more cars on subway tracks to accomodate the larger than normal crowds because all available trains are now in use.

"We just opened a bid for 90 more cars, but they haven't been made yet. It will be two more years before we can get them," he said.

"But we do have extra buses, almost 200 of the old ones," Pfanstiehl said. "The question is . . . whether we can get the money to hire the extra drivers we would need. Our budget is controlled by the eight local jurisdictions and we have to stay within that budget. There has to be a political decision to spend the money."

In New Carrollton, Anita Gilliam, a new bus rider, said she gave up her car for the first time yesterday to try public transportation.

'It was a bad choice," she said standing and waiting for a bus to Lanham. "The bus I'm waiting for is already 15 minutes late. The extra time it takes to wait for a bus is not worth it. I'd rather wait in a gas line once a week than go through this every day."

"I work hard every day, I'm going back to driving as soon as I can get some gas to get me there," said John C. Warner, a National Park Service employe who sat on a subway train last night during rush hour. But "I'm not sweating that gas line for anybody."

Bus drivers said the longer wait is not their fault. At Metro's northern division bus barn yesterday, driver Richard Casey said buses are severely hampered by long gas lines that prevent them from moving close to stops.

"I drive the 11th Street [NW] line and yesterday, there was a gas line from Harvard Street to Euclid Street in the bus lane," Casey said. "It's unsafe to have to let passengers out from the center lane when the gas line is moving like that.

"Sometimes you pass people up unintentionally because you can't see them for the gas lines," Casey said.

Drivers said they have noticed that with the gasoline shortage, the usual passenger crowd is augmented more and more with riders in three-piece business suits and briefcases.

"Oh, I can tell the new ones," one driver said."They just stand there. They don't know what to do, what the fares are or even that they have to have exact change."

Joe Greene, a driver on the 54 bus line, said, "Yesterday, you could tell the gas situation was worse than Friday because there were more people at the stops, some with books and newspapers and some of them were joking about having to ride the bus."

James Ridgeway, who works in Rosslyn, admitted being a new rider learning the bus system. "I think my bus in the 20S," he said. I'm still learning the schedule and where to stand." CAPTION: Picture, Blue Line passengers jam platform area at Farragut West station yesterday evening as rush to Metro continues. By John McDonnell - The Washington Post