It is 4 p.m., and the windows start rattling and the floors shaking in the Garten home on Southampton Drive, a suburban street in Fairfax County.

Charlene Garten doesn't have to peek through her curtained livingroom windows to see what's happening. She knows.

Laboring up hilly Southampton, in the Kings Park subdivision near Springfield, is a caravan of four orange and black trucks pulling frontend loaders on flatbed trailers.

The four trucks, which have been rumbling by the Garten home every day but Sunday for two years, are part of a daily flow of traffic -- 10,000 vehicles -- that has made two-lane Southampton Drive busier than many four-lane highways elsewhere in the state.

With a major commuter route nearby -- four-lane Braddock Road -- choked daily with cars to and from the Capital Beltway, Southampton has become something suburbanites prize as highly as a manicured lawn: a shortcut around three traffic lights.

"It's a game," sighs Donald Keith, chief engineer of the Virginia highway department's Fairfax office. "People are doing it all over. But it's probably futile. I don't think they have any idea how far extra they're driving. It's just that they don't want to have to stop."

The search for quick bypass routes worries officials and parents who fear for the safety of children on the roadsides. It also angers homeowners. Charlene Garten, who moved with her husband Edward into their split-level seven years ago, calls the street in front of their home the "Southampton Expressway."

Montgomery County has discouraged drivers in the Bethesda area by erecting Do Not Enter and No Turn signs for rush-hour traffic. Alexandria officials last year put up chain link fence to stop Fairfax County commuters from using residential streets to get to Shirley Highway.

But Fairfax County supervisors lack such authority because the streets are under the jurisdiction of the state highway department.

State officials are not inclined to restrict the practice, no matter how big a nuisance it has become. "As long as you buy gas and a license tag, you have a perfect right to use any public road in the Commonwealth," says Keith. h

He doubts that suburban tranquility is possible in a county that has about 625,000 people, with about two-thirds of them moving around every day in cars.

"The homebuyer comes to a subdivision," he says. "Everything looks nice and green. There's a nice road in front of the house. The homebuyer doesn't seem to visualize that anyone besides himself will use it. Then the first day, he drives away from his house, it's a great shock."

"My quality of life is being destroyed," Mrs. Garten says. "I don't think a residential street should have 10,000 cars and trucks going on it every day, and many of her neighbors in Kings Park agree.

"This is a busy, busy street, says Vicky Gately, a crossing guard standing at the intersection of Southampton and Clydesdale Road. "Yes, it's dangerous. You never know what children are going to do -- they're so unpredictable."

There have been no accidents yet involving the 500 children who walk to the two nearby elementary schools, Kings Park and Kings Glen. But Larane Matthews walks her 6-year-old son, Scott, from their house on Southampton to Mrs. Gately's crossing corner every day. "We got our daughter through school safely, but it's gotten worse."

Another family has had enough. "We threw the towel in," says the husband, who asked not to be named because his house is still for sale. "Our windows shake when trucks go by. You can't hear yourself think in the front yard. It's impossible for the children to play there. There have been four accidents in front and across the street."

The family's solution: "We're moving to the end of a cul-de-sac."

According to Fairfax Supervisor Audrey Moore (D-Annandale), who denounces the Southampton traffic as "dangerous," other subdivision streets on the other side of Braddock are beginning to feel pressure.

She thinks that if the highway department relieves a bottleneck just west of Braddock and the Capital Beltway, traffic will flow more smoothly, and perhaps discourage more commuter forays into subdivisions.

But Robert L. Moore, the county's transportation engineer, says: "if you solve that problem, you'll probably just move the end of the funnel further down Braddock . . . The system is overloaded, and development is continuing. There is no relief in sight."

Mrs. Garten knows all about that. When she called the federal Environmental Protection Agency to get information on the hazards of vehicle pollutants, the information officer put together some material and asked for her mailing address. When she said 5206 Southampton, the officer said, "I know where that is. I use it to get to Braddock Road."