Fairfax County is being asked to change its master use plan to permit commercial development on 273 acres at Leesburg Pike and Baron Cameron Avenue, east of Reston, but the proposal already is under attack by several members of the Board of Supervisors.

The property involved, which includes the southeast, southwest and northwest corners of the intersection, is on the master plan for residential development and currently is zoned for that use.

Property owner Mack J. Crippen Jr. and developer James T. Lewis want the county plan changed so they can construct a mixed-use development, which Lewis said would include retail, office and residential space.

Lewis said that he and Crippen will pick up the tab for the traffic improvements if the land plan is changed and the sites eventually rezoned to permit their joint venture. Lewis already has hired transportation consultants who have completed detailed designs on the proposed interchange and road improvements.

These include a grade-separated interchange at the busy intersection of Baron Cameron Avenue (Route 606), which is the main cutoff to Reston, and Leesburg Pike (Route 7), and major realignments of Route 7, Route 606 and Hunter Mill Road.

Lewis said he envisions "five-story office buildings and some retail space to support the development itself and some low-density housing." Lewis is building 17-story structures in the Tysons Corner area at his Tycon Towers project. He also is the developer of the giant Bay of Americas site in Prince George's County, along the Potomac River.

"I really see this as a chance to take the whole 273 acres and create an overall master plan for it," Lewis said.

But some residents of Great Falls and Reston are unhappy over the proposal, and two members of the Board of Supervisors said they oppose the idea.

Supervisor Martha Pennino, whose Centreville district includes Reston, called the proposal a "mini-Reston on 273 acres. There is no way that the board is going to approve this."

Pennino said, "we have worked hard to keep the area between Tysons and Vienna and Reston low density and residential, and what we have is suburban sprawl. It is the best we can do."

Pennino said she supports keeping commercial development east of the Dulles toll road along Route 7. The Lewis-Crippen application is west of that.

Dranesville Supervisor Nancy Falck said she told Lewis she cannot support his proposal. She said the existing land-use plan for the area is viable. "We have low-density residential being built now" in the area, she said.

"We have made an effort to open up the Dulles corridor with construction of the Dulles toll lanes and to relieve the traffic on Route 7 and Georgetown Pike. I am not about to take a step backward," Falck said. "We don't need to create another center for economic development. It is just a hop, skip and a jump to the Reston town center, where there is plenty of land for development."

She also pointed to land available near Herndon that is ready for the type of development Crippen and Lewis are proposing.

However, Robert Fitzgerald, attorney for the applicants, disagreed. According to the application, "The recent opening of the parallel lanes on the Dulles Airport Access Road, along with quality construction which is taking place in both the Tysons Corner and Reston areas, has caused a scarcity of land planned for high-quality office and industrial uses."

Lewis said he is not ready to get into a major fight over the sites, but he said the proposals are "a good opportunity to plan the area" and have a developer pay for road improvements. Lewis said he could work with almost any ratio of commercial-to-residential use on the three sites. He said he is not planning a regional mall, or "anything like that," and that retail space would be aimed at providing services to the development and nearby areas.

There is already some commercial development, including a service station and a plant nursery, but both are on land that already was used for commercial purposes before Fairfax implemented its master plan in 1975, according to Fairfax County. A proposal for another service station is tied up in a lawsuit.

In the application for the land-use change, Fitzgerald asked that the plan for the site be "revised to provide for PDC," which means planned development commercial, and "to allow specifically for a planned development sensitive to existing residential areas, environmentally sensitive to both Piney Run and Coldin Run and, at the same time, allow for a mixed use of residential, commercial, retail and high-quality office buildings."

Fairfax officials and citizen task forces are studying almost 300 challenges to the county land-use plan as part of the annual plan review process.

Planning Commission Chairman George Lilly has said county residents are having problems understanding the differences between plan amendments and rezonings. None of the promises made by an applicant seeking a plan change are binding on future development. Conditions can be placed on an application or promises made by a developer only during a rezoning process, not during a land-use change. In Fairfax, those conditions, or proffers, run with the land, not with the developer.

If Lewis and Crippen's proposal to change the land plan and subsequently have it rezoned is approved, it would mark the second major road improvement Lewis would be funding in the Route 7 corridor. His Tyson Towers project, west of the beltway and east of Tysons Corner, includes a four-lane bridge to be built across Route 7 leading into and out of that project.