About 200 people turned out last night for a public hearing on the controversial Springfield Bypass, although Fairfax County supervisors had already voted to approve a specific alignment for the proposed highway.

More than 40 people signed up to testify about the bypass, which would curve 30 miles through Fairfax like an outer beltway. The wisdom of building the road and the best route for it have been hotly debated since at least 1975.

Several speakers supported the road and few opposed it in concept. Most, however, represented what County Executive J. Hamilton Lambert sometimes calls the "NIMBY" viewpoint, the initials standing for Not In My Backyard. They urged the supervisors to move the route of the bypass from their neighborhood, to limit it to four lanes and to build sound and access barriers along its path.

Many of the speakers live in communities that have been built or expanded since the road was first proposed. "Simply put, the home builders beat the road builders to the punch," said Albert J. Francese, who lives on Ramrod Court in the Cannon Ridge subdivision. Cannon Ridge is one of the neighborhoods the proposed highway would only narrowly miss under the alignment proposed by state officials and recently accepted by the county.

The county accepted the state route, after more than a year of controversy, in what Board Chairman John F. Herrity said was a compromise with the state. Virginia officials promised to deal sensitively with affected communities and reiterated last year's pledge to build an access for car pools from the bypass to Shirley Highway near Franconia Road, one of the county's chief goals.

Suzanne Paciulli, representing the Northern Virginia Board of Realtors, called the proposed highway "absolutely essential to the orderly development of our county." Supervisor Audrey Moore, the road's only opponent on the nine-member board, called the road "a developers' ripoff" that will encourage growth without solving current traffic problems.