The Montgomery County Council, hoping to retain its coveted high-technology firms and attract new ones , yesterday adopted a 30-year land use plan that calls for a "corridor city" of housing, research and corporate centers in the commuter-clogged wedge between Rockville and Gaithersburg.

"This is probably the most significant land use action in the Washington region in the 1980s," declared David L. Scull, one of six council members who voted to approve the Gaithersburg vicinity master plan. The plan is a blueprint for staged but massive growth on what now are some of the oldest farms in upper Montgomery, north of Rte. 28 and west of I-270.

The only council member voting against the plan was R. Scott Fosler, who voiced concerns shared by thousands of commuters who routinely run the gantlet of major traffic snarls along feeder roads to I-270. Fosler said the plan does not fully account for sharp projected increases in traffic and probably will jack up local housing prices.

"I'm concerned we may be endangering our own economic health," Fosler said of the plan, which calls ultimately for 21,000 new housing units for 56,000 residents, 8 million square feet of office space and 30,000 new jobs.

The centerpiece of the plan, an area called Shady Grove West, is slated to become a futuristic city of biotechnology firms, corporate headquarters and a major conference center linked by local buses to the new Metro stations on the Red Line at Rockville and Shady Grove.

One of the area's planned features is a "Research and Development Village" -- complete with glass-enclosed walkways, waterways and bike paths -- that Scull said "promises to become the nation's biotech mecca."

Council member William E. Hanna Jr., the former mayor of Rockville who championed the village concept, likened yesterday's vote to the new movie "2010" -- a space-age saga "about the year we make contact" with aliens, Hanna said.

"Well, 1984 is the year the County Council made contact with the future," Hanna said. "On a scale of one to 10, everyone came out with a seven."

However, two other council members -- and scores of homeowners who live and work in the area ignominously nicknamed "Rockburg" -- were far less upbeat.

"The bottom line is that density will be too high, the development not compatible with surrounding neighborhoods and a tremendous impact on our living conditions," said Randy Davis, spokesman for the citizens association in Westleigh, a 550-home development on the west side of Shady Grove West.

Louis A. Adorian, president of the Greater Shady Grove Civic Alliance, a coalition of 16 homeowner groups, said the plan allows "too many houses and too many people. You want be able to attract the high-tech people you want. Who's going to come live here when you can't even drive around during rush hour?"

However, advocates of the plan said it contains a key safeguard to ensure construction of adequate roads to coincide with all new development. A recent tightening of the county's adequate public facilities ordinance "means that a developer can't even record his subdivision on a plat until a construction contract for that road has been signed," said Montgomery planning board chairman Norman L. Christeller.

Christeller also noted that Shady Grove West development will not occur overnight, but rather in at least three stages that preserve wide swaths of farmland and green space until later in this century.

Still, if the eight major road projects scheduled for the Rte. 28 corridor do not proceed on schedule, "development may occur before needed traffic capacity exists," according to a council report on the master plan.

Communities along the major traffic artery "may be subjected to long periods of inconvenience as a result," the report said.

Esther P. Gelman, who like Hanna is a political ally of developers who plan to build in Shady Grove West, said the master plan gives Montgomery "a place to grow. It's not perfect. It's the best we can do."