TIMES change. Movies change. Theaters change. They put roofs over their heads.

In a time of tiny, tinny theaters tucked in the corners of malls, the expansive world of drive-ins, where every car was a presidential box--and sometimes a residential suite--is struggling not to be left out in the cold. Once a major family event, "going to the drive-in" changed over the years as the movies themselves changed from G to PG to R; some drive-ins, like the Beltsville and Central Avenue in Maryland, have survived by heading into X, finding an audience after the audience stopped finding them.

In the Washington area, there are an even dozen drive-ins (including one twin). Down from 14 in 1975, that number will dip even further in the next year when the Queens Chapel surrenders to a Metro station and the Lee High- way is transformed from blacktop to hardtop in the form of six indoor theatres.

The first local drive-in, the Mount Vernon, was built in 1942; the last one, the Laurel, in 1965. Of the dozen survivors, eight are in Maryland's Prince George's County and three in Virginia's Fairfax County, a legacy of the time when those areas were rural outposts rather than suburbs. (Many other county governments managed to block drive-ins with zoning laws and licensing prohibitions.)

Drive-ins remind one of earlier, possibly better, times: when the American public was carrying on an affair not just in, but with, the American car; when gas was cheap and the miles driven somehow seemed a lot shorter; when Hollywood made movies the whole family could enjoy.

There were--and there still are--rituals and myths associated with the drive-in. On the one hand, people would try to sneak in, hidden in the trunk or squinched down behind the front seat, all to save a buck or two, but mostly to put one over. That was all right when a trunk was a trunk; but just try it in a hatchback. And neighborhood kids didn't always have the greatest respect for walls, climbing over and under, sometimes going through with a pair of wire cutters. Still happens.

Even the concessions are different, none of this popcorn and candy stuff. Almost every drive-in has a regular menu of hot food. Of course, the concession business at the X-rated drive-ins is a bit slow since people are a bit more leery about being seen. In any case, a lot of people bring their own food; a few have been known to set up hibachis (a no-no).

And, of course, there are the passion pits, the lovers' lanes, usually in the back of the lot, where the shadows are somehow longer. That's why so many communities fought against the drive-ins, though they'd list such reasonable objections as "increased traffic congestion," late-night noise and the like.

Of course, the '50s heyday for drive-ins was also the heyday for the American car: you dressed up in a Desoto or an Impala to go to the movies. Some folks would get there early with a bucket and wash their cars on the spot. You got values for money--a couple of films for a couple of bucks and no one to shush at you when you had a timely comment. Sometimes the theaters were huge playgrounds (the Beltsville once had a pond and a mechanized boat), and you could bring the whole family out for a prefilm picnic. It was the most inexpensive thing to do with your evening and still go out.

There was a time when the drive-ins were pretty well kept up, when they were ubiquitous. Like a B-movie monster, they fed on themselves and grew rapidly: before World War II, only 52 drive-ins were operating nationwide. By October of 1949, 1,500 were in operation, with another 2,000 under construction (the biggest, in California, could accommodate 7,000 cars). Now, according to the National Association of Theatre Owners, there are 3,178 drive-in screens, down from 3,790 a decade ago and almost 4,100 in 1958.

Today's drive-in stories have an ancient ring. Bill Martin, who operates the Laurel, tells an archetypical one: "One guy comes in with four bags of potato chips, two six-packs of beer, two foot-long hot dogs and he's by himself and his car's just about scraping the bottom." A little chuckle: "We let him see us and then we park next to him and wait for the pounding from the trunk . Eventually, those guys want out of there."

"What we care about is what we can see," says one ticket seller. "A lot of times kids 11 and under are free and you get 16-year-old girls coming with their fathers in pigtails, with pillows over their chests and sucking their thumbs. It's pathetic."

Passion pits. Lovers' lanes. By any name, they continue to mean the last few rows at the drive-in, and even in the liberated '80s, they at least operate at capacity, particularly on the weekends. Often there aren't even any speakers in the back, so people sit through the whole movie without hearing it.

Most everyone agrees that what has really hurt the drive-ins is the change in the movies themselves. Used to be the fare was fair, worth taking a family to, but times got harder and films got harder and ratings got tougher. When an "E.T." plays a Laurel drive-in like it did last summer, it can do a whole lot of business for six months because you just don't find that kind of family fare anymore ("they come back in for a movie like that," says Toby Trettin, who manages the concessions at the Queens Chapel). For the most part, though, movies at the drive-ins are action-oriented; "Blue Thunder" and "Psycho II," for instance, are playing this weekend. Nobody can think of a drive-in art house.

Of course, you can't get Dolby sound in a drive-in, and it's very hard to set up for 3-D. And in many parts of the country, the season is limited by the weather, which may be why California has the most drive-ins of any state (269) and Alaska the fewest (1). In the north, most drive-ins run only from March to November. When it rains, it rains, and usually there are no rainchecks. Prices are still good, though, usually two or three films for the price of one, with cartoons and shorts; plus what you save on the babysitter.

Drive-ins have changed, hardly for the better (though the ABC is set for conversion to three outdoor screens, a first for the area), mostly the worse for wear. Some are a bit rough (you can usually judge a drive-in by its bill); most stay clean and work at the perennial target of family entertainment. Capacity is a concept, seldom an achievement. During the week, it can get mighty lonely parked in the ozone. Sometimes, the weeds poke up impertinently through the cracks in the asphalt, and the potholes can be a bit rough on the suspension systems. But where else can you sit on the hood of your car and count the stars during the boring scenes? The Laurel even has 250 seats in a patio if you want a truly topless theater experience.

Where else can you sneak a look at sudden neigbors and wonder what's going on behind closed car doors and steamy windows? Midnight movies at the mall are fine, but there's no place like a drive-in for a dusk-to-dawner with coffee and donuts for the survivors. And where else is a guy going to be able to get mad and drive his truck through the wall? Happened at the Queens Chapel Drive-In once.

It'll never happen at the White Flint 5.

Metropolitan area drive-ins, ranked by vehicular capacity:

Lee Highway, Merrifield (560-1500)--1,343.

Wineland's ABC, Oxon Hill (567-4100)--1050.

Queens Chapel, Hyattsville (559-2900)--1000.

Wineland's Laurel, Laurel (776-5295)--800.

Wineland's Hillside, Hillside (736-2166)--700.

Beltsville, Beltsville (937-6655)--700.

Central Avenue, Seat Pleasant (336-3777)--650.

Wineland's Super Chief, Indian Head Highway (292-1700)--642.

Mt. Vernon, Fairfax (360-7800)--598 for Blue Screen, 371 for Red Screen.

Super 29, Lee Highway (830-8929)--500.

Ranch, Clinton (868-2900)--450.

301 Drive-In, Waldorf (843-2680)--450.