Thirty miles south of Washington, Interstate 95 is open highway. The speed limit can be exceeded safely, and is. The scenery is woodsy, the exits fewer, the traffic thinner.

Almost no one gets off at the ramp marked Dale City. Why should they? There are no hotels, resorts, restaurants, amusement parks or industrial parks. In fact, the exit sign must strike some as a joke. Dale what ? A city there in those pines?

Indeed so. A city of 30,055 persons, or more than the populations of eight state capitals.

A city that has surged up from pastureland in 1965 to nearly a third of Prince William County's population today.

A transient city, and a middle class city, full of military men and GS-7s. But a city where neighbors say hello, where a house can still be bought for $40,000, where the Little League field bleachers are painted red, white and blue.

Still, Dale City is a place where the prgram director of the civic center says he has "never seen a kid who likes it here."

A place where only two police cars routinely patrol at any hour - about one-fourth as many as would be found any other city of 30,000.

A place where the nearest grocery or school can be as much as four miles away. Where three "For Sale" signs on one block are not unusual. Where row after numbing row of identically-designed homes are all one can see.

Yes, Virginia, there is a Dale City. But where did it come from? Is it anything more than a monument to aluminum siding? Where is it going? And how is it doing?

It came from the brain and the wallet of Cecil D. Hylton. He was farming chickens in nearby Woodbridge when I-95 opened in 1958.

Hylton owned 6,500 acres just west of the highway and about five miles west of Woodbridge. It was land unsuited for farming - hilly, scrubby, full of creeks and rivers. So Hylton invented Hylton Enterprises, which invented Dale City in 1965.

Hylton has seldom talked publicly about his development since. A notoriously publicity-shy man, Hylton has delegated the running of Dale City almost entirely to subordinates and has never sat for an interview with a reporter from outside Prince Willaim County.He declined to be interviewed for this article.

Although Hylton Enterprises has always called Dale City a "planned community," it is "not a Reston and not a Columbia. It was never meant to be," said John Walvius, Hylton's vice president.

The difference is not only home prices, which average $12,000 less than in Reston or Columbia for comparable features, but lack of local employment.

According to Prince William County planning office figures, more than 16,000 adults live in Dale City, but only 6,787 work there. Most of the others work in or near Washington.

"We didn't envision a strong internal community," said Walvius. "We wanted a place where good, big homes could be bought at a reasonable price. I think it's turned out far better than the traditional subdivision."

But many disagree.

"What Hylton has done to the land there is almost unspeakable," said Jim Gracie, a country planner. "The problems are just endless."

According to a report on Dale City compiled by the county in 1974, Hylton's dense development on quarter-acre lots has produced serious environmental difficulties.

Because the land is now nearly bald, runoff during heavy rains has sometimes polluted water sources, the county found. Construction of homes in deep valleys has produced "a possible threat to life in future floods," the county said. All in all, the report said, the spirit of the county's open space planning standards "has been abused badly in Dale City."

The houses themselves, 8,110 at last count, have come in for their share of criticism, too.

"I've been in lots of them. On a windy night, you see the drapes blowing out," said Mike Clark, program director of the civic center. One realtor calls the houses "big, but nowhere near as well made as they should be."

But the houses are selling anyway. Like hotcakes.

Pete Stoebe, sales manager of Blue Ridge Realty, which does considerable business in Dale City, said his trade was up 50 per cent in 1977.

Stoebe said 15 per cent of Dale City's homes turn over in a typical year. In addition, he said, a Dale City home is usually sold and transferred within 60 days - about half the Washington-area average.

What does the buyer get? "You can buy a four-bedroom, detached house with central air and a fireplace for $55,000," said Penny Salome, a realtor for Town and Country Properties Inc. "Where else is that possible?"

In few places closer to Washington, certainly, and throughout the Dale City's existence, the same has been true. As a result, Dale City expanded at a furious rate.

Six thousand people lived there in 1968. More than 22,000 lived there by 1973. Today, construction is underway in Nottingdale, the 14th alphabetically ordered Dale City "community." By 1990, Dale City's population is expected to be 47,340.

But because growth was so quick, Dale City has spent much of the past decade catching up.

Until 1971, the city had only one elementary school. It now has three, as well as two junior high, or "middle," schools. But class sizes average 45, higher than anywhere else in the county.

Until 1976, Dale City had no recreation center. There are still only two full-service groceries, two sit-down restaurants and one movie theater.

Meanwhile, gaps remain, some of them fundamental.

Dale City has no local newspaper. No local radio station. No bars. No police department or police station. No hospital. No high school. No internal public transportation. No mayor. No city council. Not even a McDonald's.

The nearest high school or hospital is five miles away, in Woodbridge. Dale City has two volunteer fire departments, with some paid round-the-clock staff, but until eight years ago, clergymen were on call during the day because they were the only available males.

Dale City's schools are "neighborhood schools" in flavor and traditional in educational approach. But this is a community that is six miles long and as much as eight miles wide. As a result, more than half the elementary and middle-school pupils are bused to school. Some students live as much as four miles from the schools they attend.

Trying to telephone Springfield, only 15 miles away, can startle the unprepared. It's a long distance call, as are all calls outside Prince William County. And Dale City does not even exist as far as the U.S. Postal Service is concerned. It has been assigned zip code 22193, but 22193 is officially Woodbridge.

Then there is the saga of Dale City's I-95 interchange.

Built as a "country style" diamond, it worked well at first.But since the peak of Dale City's fastest growth in 1969, the problem has been very simple: You can barely get onto I-95 in the morning.

To get out of Dale City in the most direct fashion, one must drive six miles along Dale Boulevard, the city's stoplight-studded main drag. Then a right onto Smoketown Road, which is one lane in each direction. Then a left, when one can, across oncoming traffic. Then down a one-lane access ramp to I-95.

The result is morning rush-hour backups, often three miles long, with cars spilling halfway back into the city. On especially grim days, it can take as long to get from the Forestdale subdivision to I-95 (four miles) as from the Dale City interchange to the Pentagon (27 miles).

A solution is expected by late 1981, according to county transportation planner Steven D'Antonio.

A largely federal grant of $21 million has been appropriated. It will be used to build a full cloverleaf at the Dale City interchange, which will allow direct, medium-speed access from Dale Boulevard to the highway.

Meanwhile, Dale City seems to work for most commuters, despite the distance they have to cover. And lately, a town that was once sneered at on the "military grapevine" as being too "plastic" or too far from anywhere else is beginning to keep some of its residents.

"We decided to retire here," said Kathleen McCoy, who has lived in Dale City for eight years and whose husband is a retired Navy officer. "We had lived all over the world and had never been anywhere where my daughter could do anything but join the Girl Scouts.

"Here, there are lots of things. And if I went into the Giant and somebody didn't say 'Hello' or 'Have a nice day,' something would be wrong."

"I'd never live closer to D.C. Even Alexandria," said Gwen Dalton, the wife of an Army sergeant and a Dale City resident for 18 months. "No way I'd live in that mess. I don's like to have to set through three red lights to make a left turn."

But many young people, especially teenagers, see it very differently.

"Yeah, I come here a lot," said Kenny Sigler, 16, of Dale City, one recent afternoon as he played pibball in the civic center. "What else is there to do here, man? It's boring if you don't have no money or no car. Nothing's free no more, man."

Sigler said he has tried to find an after-school job, "but they don't have no jobs around here. I could get one in Woodbridge, but I got no way to get there."

Mike Clark has heard the refrain many times.

"The kids are bored. They really don't know what to do with themselves. And the parents here are under a lot of pressure, commuting, working two jobs. A lot of the kids are left to fend for themselves, and they don't really know how," he said.

Clark told of civic center regulars who "shoot off .32s in the parking lot, just to be big," and who drink and use drugs. One young man severely beat Clark with a pool cue in Clark's office earlier this year.

A cause of restlessness may be Prince William County's year-round school system.

Students are at school for nine weeks, then off for three, 12 months a year. As a result, many young people have unwieldy chunks of time on their hands.

Three weeks is seldom long enough to take or get a part-time job. And time seldom "fits" with the vacation schedules of the rest of the family. In addition, truancy is at an all-time high, according to Sgt. Raymond Williams, commander of the county police's youth division at the Garfield substation.

"But most of these kids are good," said Clark. "I feel it's a small percentage that's causing the problem."

Sgt. Williams agreed. "Maybe 10 or 20 kids are doing it," he said. "It's the same ones all the time. I've got files in here on some of the them that it takes both hands to hold." In general, however, Sgt. Williams said, Dale City's crime rates are "exactly the same as the rest of the county."

Will any of Dale City's problems change, or abate? No one in the city's equation thinks so.

The only certainty about the community's future is that it will grow - probably by about 500 units a year, according to Walvius. Meanwhile, said Clark, "Dale City is no longer a new community. It's got pluses and minuses . . . It's becoming just like everyplace else."