Fairfax County officials are considering a controversial plan that would allow the construction of dozens of high-rise buildings along the roads leading to Tysons Corner.

The county planning staff's proposal, now before a citizen task force, calls for the construction of huge "gateways" consisting of tall buildings on each side of intersections leading to Tysons, which critics point out is already one of the region's most congested areas.

Many Fairfax County residents, who say the area is already overbuilt, are alarmed that the plan would allow high-rise construction to stretch outward from Tysons Corner alongside residential neighborhoods, in areas previously set aside for low-rise buildings.

Under the proposal, buildings as high as 22 stories -- up to 215 feet tall -- would be used by planners to "introduce" motorists to Tysons, which county officials call Fairfax's "new downtown." The high-rises would be at key intersections along the Capital Beltway, the Dulles Access Road and Rtes. 7 and 123.

"We just don't buy it," said Stephen Hubbard, chairman of the McLean Civic Association's planning and zoning committee and a leading critic of the county plan.

"We just don't believe you can have such tall buildings on the Tysons perimeter and not impact residential developments," Hubbard said. "It will change the character of the area out here."

Richard G. Little, a division head in the Fairfax Office of Environmental Planning, takes sharp exception to that. He said the high-rise "gateway" concept merely "calls attention to the transition from a rural-residential area on one side of the highway to a major commercial center" on the other.

"I certainly think this concept is valid," Little said. "We're trying to market Tysons Corner as the premier office center in the county." The gateways, he said, "are a way of telling people that they're entering some place different."

"Since when do you need a tall building to announce to someone that they're in Tysons Corner?" Hubbard shot back. "A sign works just as well. We already have the largest concentration of offices in the state. We want it to avoid swallowing all of us."

Some of the Fairfax County supervisors, who ultimately must decide on the plan, have expressed reservations. Although the plan was released in December, the board only recently named 16 Tysons area residents to a citizen task force to review the height study. Public hearings on the issue will be held before the county Planning Commission and Board of Supervisors around Jan. 1.

Commercial intrusions into the neighborhoods around Tysons and traffic are the principal concerns of Hubbard and others in the area.

Like much of the rest of Fairfax, the Tysons Corner area is beset by severe traffic problems that make driving there a major headache. Promising to incorporate traffic improvements, developers recently broke ground for "Tysons II," designed as a near-twin to the economically thriving commercial center there.

Liberalizing the zoning requirements at Tysons "would be a more appropriate concept if we had the highways to handle it," said Carl L. Zimmer, chairman of the citizens task force.

"We don't think the existing or planned transportation network can handle that intensity," Hubbard agreed.

The emergence of such pessimistic forecasts has worried many Fairfax County politicians and planners who until recently were confident they had gained the upper hand on Tysons' problems.

Little said he was taken aback by the hostility generated by the height study. "My belief is that this study is a relatively conservative approach," he said. "What we're proposing is by no means extreme. We're not talking about a large number of very tall buildings."

Little defended the plan as a realistic response to the development that already has occurred at Tysons, including some of the high-rises that have been approved around the edges of the area. The Board of Supervisors, for example, has allowed construction of a 215-foot-high Sheraton Hotel at the intersection of Rte. 7 and the Dulles Access Road, an area that was previously set aside for buildings no higher than 75 feet.

Supervisor Martha V. Pennino, vice chairman of the Board of Supervisors and sponsor of the zoning change approved for the Sheraton, said she favored the height exemption as an alternative to an increase in the hotel's "bulk." She said residents in the nearby neighborhoods of Tysons Green and Westbriar Hills generally supported her decision.

Pennino disputed assertions by some critics that the Sheraton decision set a precedent that will make it difficult to deny similar rezoning requests in the Tysons area. "Each individual case is different," she said.

She gave high marks to the county planners who drafted the height study, saying she favors the gateway concept. Pennino said, however, that she will vote against it "if the overwhelming sentiment of the citizens" runs counter to the staff plans.

Supervisor Nancy K. Falck, who represents the Dranesville area north of Tysons, and Supervisor Audrey Moore of Annandale opposed the rezoning.

Falck said she remains opposed to allowing high-rises on the periphery of Tysons Corner. Falck said she views the Sheraton "not as an excuse" for further high-rise construction but as an "aberration" from desired county zoning laws. "We're having a hard enough time dealing with Tysons as it is without adding to the problems."

In addition to relaxing county height restrictions at that site, the supervisors eased the 75-foot height limit at Rte. 7 and the Beltway for the construction of the Tysons Tower office building, which will stand 204 feet high.

"Ignoring those buildings would not be realistic," Little said. "Decisions have been made, and the board has now asked us to look at the next applications down the road . . . . How can we say to developers that we allowed those structures and then tried to change it for everyone else?"