More than 85 percent of the roughly 1,500 service stations in the Washington area will be open today, and about 10 percent should be open Sunday, according to the District of Columbia branch of the American Automobile Association.

Meanwhile, there are signs that Washingtonhs motorists are beginning to adjust to the reality that there is about 5 to 15 percent less gasoline available. Last weekend, large numbers panicked and mobbled many stations in seeking to "top off" their tanks.

Yesterday, there were fewer lines at area service stations, and they were shorter than those of the previous Friday.

"People are a little calmer. There's adequate gas out there if people don't panic," said Glenn Lashley, a spokesman for the D.C. branch of AAA.

It seems that motorists are finding small ways to save gasoline. Metro bus and rail ridership was higher than usual last week, some downtown parking lots noticed a 20 percent drop in customers and bicycle shops did a booming business.

Virginia Gov. John Dalton, Maryland Gov. Harry Hughes and District of Columbia Mayor Marion Barry conferred by telephone yesterday on the gasoline situation and concluded that local rationing plans are not yet necessary.

Dalton said motorists "appear to be exercising restraint in gasoline consumption." He noted that Virginia has only 92 percent of the gasoline available that it had this month a year ago, which makes conservation "essential."

For the most part, Virginia and Maryland state police said, rush-hour traffic on the Capital Beltway and major arteries appeared to be normal, but there were some strange departures from normalcy, too.

Just before dark on recent nights, Maryland State Police Cpl. Kenneth Pollock and his partner noticed that traffic was exceedingly light on Interstate 95 near the beltway.

"I couldn't believe it," he said. "It looked like 3 a.m. in the morning at 8 at night.... You could really see the difference. People were staying home."

Pollock said he has also noticed that long-distance vacationers are fi lling up the motels at sunset instead of driving late."Everybody's scared, they all shuffle in when sunset comes."

Vacation trip planning requests to the D.C. branch of the AAA are down 14.8 percent compared with last year, according to Lashley.

A woman waiting in line yesterday at an Exxon station on Rockville Pike, Elaine Davis of Rockville, said she and her husband traded cars to save gas because his used less gas and she does more driving than he does.

"Last week this time I waited 45 minutes and today it was only 5 minutes, so I guess it's not so bad," she said.

Many people interviewed at service stations yesterday said they were aware of the problems that arise when everybody tries to "top off" their tanks for the weekend-that this sort of panicky behavior drains reserves from the ground and makes the problem worse.

Nevertheless, some people continued to do it.

The first customer of the day at Penneyhs Gasoline in Springfield Mall waited half an hour for the station to open yesterday morning and then asked the attendant to "fill her up."

Her tank took only another 50 cents worth before the gasoline brimmed over onto the pavement.

Many people said they had trouble, not because many stations were closed, but because they would drive into an open station and it would be out of unleaded gas.

"We're getting a lot of people coming in here whose cars are only supposed to take unleaded gas and they have ripped the caps off," said Alexandria Sunoco dealer Ralph du Brueler, speaking of the small metal onstructions, or "caps," inside unleaded tanks that make the tank's hole smaller so that only the smaller unleaded-nozzles, and not the larger regular nozzles, will fit into it.

"I had four of them in the last two days," du Brueler said. "I won't serve 'em. One guy pulled out of here, wheels squealing, cursing, saying he was going to bring back the shefiff and force me to serve him. He never came back."

The Environmental Protection Agency has said it is concerned that the higher prices of unleaded gasoline will encourage more people to use regular in cars designed for unleaded - which will destroy the sensitive antipollution equipment on the cars.

If drivers of cars needing unleaded encounter shortages when regular is available, it is thought more of them may use regular, thus adding to the problem.

Supplies of all types of gasoline for this area have been curtailed by about 5 to 15 percent, it is estimated. But supplies have also been curtailed by similar amounts in most areas of the nation, leading to speculation that there was a stronger reaction in this area than in most places because people here tended to follow the news more closely as Congress debated and defeated a national gas rationing plan two weeks ago.

The AAA spokesman said yesterday that, next to California, the lines and panic at gas stations has been worse in this area than anywhere else in the nation.

Joseph Crisafulli, owner of Wheaton Sports & Cycles Inc., said that recently there has been a "boom" in bicycle sales because of the gasoline shortage, the nice weather and a new consciousness of staying slim.

"People mention the gasoline thing," he said. "They say they're going to ride to work or ride to a parking area so they can take a bus." He said that bicycle sales are up about 50 percent and that 20 percent of that is accounted for by the gas shortage.

Laverne Paige, a cashier at the huge Apcoa parking lot on 14th Street NW behind the District Building, said that there have been at least 20 percent fewer customers this week following the panic last weekend.

"It's been slow all week," she said. "See those empty spaces over there? Usually, those are all filled up."

On Wednesday, Paige said, there were only 2,200 cars in the 3,000-car lot.

Christopher Nicholson, manager of an MCM parking garage at 1101 15th St. NW, said that business has been down all week following the weekend of the gas rush. He said the lot, which holds 206 cars, is usually full. But on Wednesday, for example, only about 170 cars parked there.

An executive of PMI parking, which has about 100 lots and garages in the District and Northern Virginia, said that business dropped off this week but that it wasn't clear if the gas shortage and panic caused it. Business usually goes down this time of year with nice weather, he said.

There were increases this week in Metrorail ridership, and an apparent increase in bus ridership, but a spokesman for the Washington Metropolitan Area Transit Authority said this could not necessarily be attributed to the gas panic.

Metrorail ridership went from an average of 229,000 daily trips two weeks ago to an average of 238,000 for the first three days of this week, according to Metro figures. Supervisors at three key locations for transferring from subway to bus on Tuesday night all reported that bus ridership seemed to them to be heavier than usual.

But the Metro spokesman said any increase was "no big jump" and could be due to parkway construction or good weather.

While supply was the main concern for motorists yesterday, price also played a part. Where there were lines, they seemed somewhat longer at the cheaper stations, such as Crown in Rockville.

The average full-serve price for gasoline in the area last week, according to the AAA, was 82.3 cents for regular, 87.1 for unleaded and 88.5 for premium. CAPTION: Picture, Lines formed early yesterday at a station on the corner of South Capitol and I streets SE. Except for California, AAA says the lines have been worse here than anywhere else in the U.S. By Joe Heiberger-The Washington Post