Back in 1958, when a Virginia highway engineer first proposed running an interstate roadway across Fairfax and Arlington counties into the District of Columbia, Steven Malone was in a first-grade class in New Jersey and was dreading a tonsilectomy.

Today, 23 years of emotional public hearings and bitter lawsuits later, that highway is on the verge of opening to traffic, and when it does, Steven Malone will be there.

He has been one of I-66's environmental monitors for two years, and like the hundreds of workers involved with the $170-million project, he finds it hard to believe its completion is in sight.

But it is. A small portion of I-66 will open inside the Capital Beltway in less than three months. On Nov. 1, buses will travel a one-mile segment of the highway between Sycamore Street in East Falls Church and Fairfax Drive in Ballston.

In the spring, 7 more miles of I-66's final 9.7 miles will be open to bus use, leaving only the area between Fairfax Drive and Rosslyn in Arlington still under construction.

If the project remains on schedule, highway department officials will open the the entire roadway to private automobiles in the fall of 1982.

It's been a long time coming for the commuter highway that will link the Beltway with the Theodore Roosevelt Bridge and shave 15 minutes off many Washington commuters travel time. Virginia highway officials who had to overcome strong area opposition to get the project approved, promise that the roadway will be unsurpassed in the Washington area in terms of highway technology, traffic management and aesthetic features.

Traffic on the limited-access, four-lane highway will be monitored by an elaborate televsion camera system, motorists will be flashed traffic advisories on electronic signs, and have their entry on the roadway controlled by electronic gates at each of the highway's seven interchanges. "It's the state of the art system," brags I-66 environmental monitor Keith Argow.

Engineers claim the road itself will look more like a parkway than a typical interstate because of its extensive landscaping, bike and hiking paths, two-tone bridges, color-coordinated pavement, and an expensive pedestrian plaza with fountains and park benches that will cover the highway in Rosslyn.

But it will be a highway and one that is expected to carry an estimated 3,370 cars and 111 buses during an average rush hour. That's relatively light traffic compared to the tens of thousands of communters who use Northern Virginia's Shirley Highway, Washington's busiest communter road.

Not everyone will be allowed to travel the new I-66, the engineers note. Under the restrictions set by an agreement with the federal government, rush hour traffic will be restricted to cars with four riders, buses, and traffic to and from Dulles International Airport.

Although highway officials have yet to set exact times for the rush-hour restrictions, they said the inbound traffic will probably be limited weekdays between 6:30 and 9:30 a.m. and outbound between 4:30 and 6:30 p.m.

The four-to-a-car rule was established in 1976 by then-Secretary of Transportation William T. Coleman Jr. who agreed to support construction of the highway if Virginia officials would scale it down from four to two lanes in each direction and impose severe restraints on its use.

State officials say they are obligated to carry out those restriction and point out that the highway contains 10 "enforcement areas": alcoves on the highway's shoulders from which police squad cars can watch traffic.

At the same time, 10 television monitors will relay pictures of the roadway back to a building on Columbia Pike, where traffic engineers can watch the highway and close entry ramps by remote control, supposedly eliminating any bottlenecks.

True, this might cause even messier traffic jams on the ramps, especially since engineers doubled the number of ramps on the highway to insure there would be no excessively wide interchanges. But . . . .

"Worse comes to worst they could make a U-turn on the ramp," said Malone.

"Or fight the traffic on Rte. 50 and on Rte. 7," offered Argow.

Officials would rather point to I-66's planned prettiness.

Travelers on the highway will be able to view landscaping that includes newly planted White Oak, Rosewood, Dogwood, White Pine and Rhododendron. And they'll be able to enjoy at least one Horse Chesnut tree, preserved by landscape architects thanks to some minor redesigning of the project near the Circle Towers Apartments in Arlington.

It took extensive planning to create what is perhaps the project's most elaborate amenity: a pedestrian park plaza above I-66 in Rosslyn. More than 900 square feet, the plaza will extend from Fort Myer Drive to Lee Highway and from Nash to Lynn Streets. It will feature an outdoor ampitheater, several fountains, bike paths, and food stands.

Designers of the multimillion-dollar pedestrian park said that the area was built to transform what might have been a canyon of underpasses and overpasses through Rosslyn's already-congested, high-rise district.

Equally impressive, the planners claim, will be the use of the highway's median strip to carry Metro trains on the Vienna Line westward from the Glebe Road area where it emerges from a tunnel. The subway, however, is not expected to begin running there until 1985, the highway officials say.

For the estimated 12 minutes that the average motorists will spend on the roadway, he can observe its planned rusticity, supposedly accomplished by such details as rough-hewn wooden handrails on top of concrete retaining walls, bridges painted two tones of brown, and reddish gravel shoulders that engineers say will soften the impact of the highway's black asphalt and blend the road with the wooded surroundings.

Lining the highway at points will be Sierra Wall, a sound barrier that the highway department heralded earlier this summer for having aesthetic values. Other sound walls are constructed of steel or concrete, but they almost always are hidden by wooden facades. Where there are no neighborhoods to protect from noise, environmental engineers have opted for chain link fencing in what was deemed the most unobtrusive color -- black.

In keeping with that countrified mood, I-66 designers met citizen demands and lined the roadway with bike and hiking trails, complete with their own on-off ramps to facilitate short trips.

Some sections along the paths have been landscaped as carefully as the highway itself. Near the Washington-Lee High School in Arlington, I-66 designers built two ponds for nature-study classes.

The ponds are not visible from the highway and "They're purely for the benefit of the community," said Argow.

Several design details -- most notably the lighting of the roadway -- remain embroiled in controversy. After an emotional meeting with highway officials last month, Fairfax County residents won a 30-day period in which to present lighting design alternatives to the proposed plan of illumination from the road's shoulders.

According to highway department officials, however, this will not delay I-66's construction. It's almost complete, and said State Highway Commissioner Harold King: "Nothing is going to stop it now."