The Fairfax County Planning Commission recommended approval last night of Tysons II, a proposed 107-acre office, shopping and hotel project that some county residents fear would choke roads with traffic in the Tysons Corner area.

The commission voted 10 to 0 to rezone the largest remaining undeveloped tract in the Tysons vicinity -- an area that has been called "downtown Fairfax."

The commission's approval was a significant milestone for the Tysons II project, which would cost at least $400 million to construct and has stirred controversy since it was first proposed more than a decade ago. The project now goes to the county Board of Supervisors for final consideration Oct. 15.

Last night's vote came after John T. (Til) Hazel Jr., attorney for the project's developers, H-L Land Improvement Venture, had guaranteed the county $14 million in road construction improvements designed to handle increased traffic generated by the development.

"We think we have done enormous things to address transportation problems for Tysons," Hazel said.

Nonetheless, some residents of the area told the planning commission they thought Tysons II could cause major traffic tie-ups because the developers had not provided for adequate road improvements in the area.

"The traffic is going to be tremendous," said Gloria A. Adams, president of the McLean Citizens Association, whose efforts to exact further road concessions from developers were ignored by the commission.

The site, north of Rte. 123, just across the road from Tysons Corner shopping center west of the Beltway, has been described in advertisements as "probably the most valuable property on the East Coast."

The development is a joint venture of Homart Development Co., a Chicago-based subsidiary of Sears, Roebuck and Co. and Tysons II Development Co., a Bethesda-based concern headed by Theodore N. Lerner, a Washington shopping mall magnate who has developed malls at Tysons Corner, White Flint and Landover.

The developers plan to build two large hotels, a series of office towers and a three-story, galleria-style shopping mall to be anchored by major department stores, such as Saks Fifth Avenue and Macy's.

"I think this will be a focal point for the county," said Dranesville planning commissioner George M. Lilly. "It will also be an obvious financial benefit to the community." The scheme is expected to generate millions in tax revenues for the county.

Citizens concerned with traffic congestion in the vicinity of the project have pressed the developers for two bridges spanning Rte. 123 to avoid backups at intersections on the road. The developers, arguing that two spans are unnecessary and technologically impractical, have offered to pay half the cost of constructing one bridge over the road, which would connect Old Westpark Drive on the Tysons II side of Rte. 123 to the Tysons Corner side.

The planning commission also voted to require that the developers submit all architectural plans for Tysons II approval -- a plan that Hazel called unacceptable.

"You can't design a development in the planning commission," he said after the meeting. "There's no way we'll agree to that."