I-66 is a road and an issue that has caused virtually every Washington area jurisdiction and every federal agency associated with it to switch pasitions at least once during the last 20 years.

Only the Virginia highway department has been constant in its determination to build something along the 9.7 mile right-of-way it has now spent almost $30 million acquiring, even if it can't build the 8- or 6-lane interstate "super highway" it wanted in the 1950s and 1960s.

Plants have since dwindled to the presently proposed four-lane, no-truck "parkway," to be used during rush hours only by car pools, buses, emergency vehicles and Dulles-bound cars. But even this compromise is opposed by civic groups whose latest suit to block it is scheduled to go on trial Tuesday in U.S. District Court in Alexandria. The court has ordered Virginia not to start construction, which was to have begun last week, until the case is decided.

Barring a long trial, the road is expected to be completed within four years, Virginia highway officials said this week. When it is opened to Theodore Roosevelt Bridge, to District probably also will limit the bridge to buses and carpools, at least during rush hour, according to D.C. highway officials. Trucks already are prohibited on the bridge.

Virginia's announcement June 21 that it was awarding a $9.6 million contract to began construction of I-66 from the Beltway to Route 7, with bulldozing expected to begin in two weeks, is not the first time the state has announced that construction was imminent. Such announcements have been made almost semi-annually since 1959. A $3 million contract to build match the same section of I-66 was awarded by Virginia in 1963, and though engineers began staking out the route - as they have been doing for the past three weeks - ground was never broken.

I-66 is not the only unbuilt interstate highway around the nation's capital, although the dispute over it has lasted the longest. The East Coast's major North-South route, I-95, has a missing link in the District and Montgomery County because of the opposition of local residents, and several proposed downtown and crosstown freeways and the Three Sisters Bridge similarly have been killed.

Envisioned as a 65-mile interstate throughway from the Shenandoah Valley to Washington, I-66 was in trouble in the 1950s even before it could get across the Potomac River.

Powerful highway interests forced early construction of Theodore Roosevelt Bridge, to carry to future I-66 into Washington, over bitter opposition of the National Park Service and the Fine Arts Commission. But President Eisenhower confounded the highway before he left office by permanently banning truck traffic from the bridge. The bridge, which cuts across the George Washington Memorial Parkway and Theodore Roosevelt Island, a nature sanctuary and memorial to the conservation-minded President, put more than 10 acres of highway ramps by the west end of the Mall near the Lincoln Memorial and funnelled most of its traffic directly on the Mall - including roads where truck traffic is banned.

The no-truck decision forced highway planners to attempt to build yet another bridge for I-66 traffic. Three Sisters Bridge, called the I-66 truck route when it was first proposed. It in turn would have forced additional highways through parkland along Spout Run Creek, the George Washington Memorial Parkway and the C & O Canal, as well as crossing the Potomac above Georgetown at one of the river's most scenic spots.

When the Three Sisters Bridge idea was finally killed, it forced the I-66 route back through Rosslyn to the no truck Roosevelt Bridge. But I-66 opponents thought they had killed I66 entirely in August 1975, when Secretary of Transportation William T. Coleman announced that no federal funds could be used for the section of the road inside the Beltway. "This is simply the wrong time and the wrong place" for such a highway, he said, and suggested both area transportation needs and the environment would be better served by putting Metro in the right of way and improviing existing roads!

However, Coleman reversed himself last January shortly before he left office, a controversial decision that rankles many Arlingtonians - especially those who bought houses near the I-66 right of way within the past two years on the strength of Coleman's orginal decision.

His witch came after Virginia agreed to what Coleman called a "substantially different" I-66 proposal, a four-lane, no-truck parkway designed to limit its impact on the parkland and neighborhoods it passes through. But the crucial reason apparently was that Virginia would agree to "advance the completion" of the Metro subway system in Virginia, which Gov. Mills Godwins has called a "boodoggie" and denied state dunds for. The state now has agreed to transfer $30 million in highway funds for Metro construction and to build the I-66 median, where Metro would go, so it will save the subway another $45 million.

In February, new Transportation Secretary Brock Adams said his "commitment is to the Metro system," and reaffirmed the present federal position on I-66.

Now, however, Metro isn't sure it wants to build a line along I-66 at all. Its Fairfax County representatives contedna subway out to Falls Church and Vienna isn't needed any longer since I-66 will be a bus and car pool highway during rush hour. No decision on Metro is expected before fall.

"It boggles the mind," says Hank Levine, attorney for the Arlington Coalition on Transportation (ACT), which sued to stop I-66 in 1972, permaturely celebrated its demise in 1975 after Coleman's pronunciamento, and again sued to stop the high-way this spring.

The present lawsuit claims, among other things, that Coleman's January decision on I-66 was an illegal "political deal," and that the environmental impact statement Virginia prepared on I-66 is inadequate, "a piece of junk," says Levine. "The EIS assumes Metro will be built but everybody knows they're not going to build the Metro line out there and if you don't have Metro then Coleman's argument, the whole thing, crumbles."

Nor does the EIS consider the impact of "the tens of thousands of cars a day I-66 would dump in the District. It stops at the state line in considering the effects of I-66," says Levine, who is associated withe fhe large Washington law firm of WIlmer, Cutler and Pickering. The firm is handling the case without fee.

Among I-66's adversaries is the District of Columbia, which rammed through Teodore Roosevelt Bridge and now, with a change of officials and thinking, opposes the highway for which it built the bridge. D.C. Transportation Department Director Douglas N. Schneider Jr. said in Senate testimony in May that I-66 will further aggravate Washington's traffic and parking problems.

He also said he didn't think plans to limit the four-lane road to car pools and busses would work because "I don't think there are enough buses and car pools to justify building it," and then there will be "tremendous pressure" to allow general traffic on I-66. "Frankly I think that's what the strategy is," Schneider said.

ACT temporarily blocked I-66 in the courts from 1972 until last February, but "We still haven't had our day in court and while it may look like we've been losing we've just been waiting," says Levine.

U.S. District Court Judge Oren R. Lewis, who will hear the present ACT suit, had issued the 1972 injunction against the road. He ruled that Virginia could not build it until additional public hearings were held, and environmental impact statement prepared, and the road was approved by the Secretary of Transportation. When Coleman's blessing came in January, Lewis dissolved to injunction and said "It seems to me if they have done A, B, C and D then they can proceed to build it . . . we are not here to retry I-66."

Onl July 15, when setting the new trial date, Lewis said to ACT, the D.C. Federation of Civic Associations and other groups opposing the highway, "You're not going to delay this road forever. There comes a time when the good citizens of North Virginia . . . and the District - I'll put them all together - have a right to know the finality of (I-66)."