With I-66 open and a construction contract let for for the parallel lanes along the Dulles Access Road, the Springfield Bypass remains Fairfax County's last major unconstructed and controversial transit link.

But with a history no less controversial than that of I-66, the bypass, which has been on the county's master plan since 1975, still has a long way to go before it will ever become reality.

As its name implies, the bypass was conceived as a short detour around congested Springfield to the Shirley Highway. But in the years since it first appeared, it has grown into a 35-mile, $200-million Outer Beltway that would curve from Rte. 7 and Reston in the north to Rte. 1 and Mount Vernon in the south.

The exact route of the bypass has been the subject of controversy for more than a year. It became an issue in last year's gubernatorial election and led to the downfall of a Virginia state highway commissioner. Only last week did the Board of Supervisors place a final alignment for the bypass on the county map.

Among the barriers before the bypass are such items as an environmental impact statement and design hearings, which county officials expect will rekindle fights about the size and nature of the road.

As currently envisioned by county officials, the bypass would have four lanes with at-grade intersections to minimize its intrusiveness. State highway officials, however, say the road must be six lanes in many places, with some cloverleafs, or it simply won't handle the traffic.

Even once those disputes are settled, however, the county must find money for the road. Most officials say it will be built in chunks, with developers helping fund sections that are important to them and the rest of the road being built gradually.

Supervisor Audrey Moore, the road's only opponent on the nine-member board, says the road will end up stimulating growth. She points out that most of the land to the west of the bypass is undeveloped, and she argues that the county should improve its existing commuter routes before spending money on new roads.

One wag at a public hearing recently dubbed the bypass the "circum-Hazel" because it passes by so much property owned or developed by influential zoning lawyer John T. (Til) Hazel. Proponents, however, call the road the "Fairfax Parkway" and say it is essential for intra-county travel.

In a few years, board Chairman John F. Herrity likes to point out, most Fairfax commuters will make their entire trip within the county instead of driving to jobs in Alexandria or the District.

With the chamber of commerce, the Northern Virginia Board of Realtors and most of the county's politicians pushing for the road, money for it likely will be found. The only real question is whether opponents along the route can achieve substantial delays in court as their I-66 ancestors did a decade ago.