The Arlington County Board has cleared the way for the redevelopment of a central Clarendon site into a five-story office building that would be the first project built under a new zoning created to spur the area's revitalization.

Unlike redevelopment projects in other areas of the county, the board did not vote on the specifics of the proposed building, but gave unanimous approval for the land's reclassification into a new zoning that includes caveats on height, the mandatory placement of parking and utility lines underground, and the designs of streets and sidewalks.

The new zoning category, known as the commercial-redevelopment district (C-R), was specifically designed to encourage developers to submit plans that would rejuvenate Clarendon, the county's once-thriving commercial area..

It is one of two new zonings the county created to give Clarendon a boost; the other is a commercial town house category. Both were adopted with the goal of providing nearby residential neighborhoods protection from high-rise encroachment by calling for a lowering of heights as buildings get closer to single-family areas.

The rezoning the board approved last week is "a very positive note because we've been encouraging developers to come in under that," said James M. Wright, a member of the county's Economic Development Commission and organizer of the fledgling Clarendon Alliance, a coalition of Clarendon-area businesses and residents who want to join with the county in promoting the area.

Albert C. Eisenberg, the County Board's vice chairman, said he also thought the proposal was an encouraging sign: "If some developer finds this site can be properly developed using the new zoning, then I think it sends an important signal to others in the C-R district that it's something worth doing."

Eisenberg added, "Landowners will no longer have to wait to see what's going to happen there. Clarendon is happening right now and they can get on with the business of revitalization, which is what the surrounding neighborhoods and the county want them to do."

The land that the board rezoned last week is in the core of Clarendon on a one-acre tract bordered by N. 10th Road and N. Highland, Hudson and 10th streets. The site of the Lyon Apartments until last year, the land is behind the main post office and two blocks from the Clarendon Metro station.

The developer, Highland Properties Corp., did not have to submit specific proposals on the building to the County Board since the board decided, in drafting the new zoning, that developers would have an automatic right to build any office or residential structure that meets the zoning's requirements.

Richard R.G. Hobson, the developer's attorney, said that the initial plans calling for a five-story office building may be altered to include a residential segment because county officials expressed concern that apartments were razed to make room for the proposed building.

County planner Terry Russell said developers in the C-R district get extra density if they include residential buildings in their plans.

The new C-R zoning, Russell said, will replace the older commercial zoning under which many of Clarendon's small stores and shops were built decades ago. The old zoning, which some developers may still want to build under, sets a 75-foot maximum height, while the C-R allows heights to taper up from 55 feet to 110 feet.

Because the C-R zoning was created for a small area close to the Clarendon Metro stop, the required number of parking spaces is lower than under the old zoning, Russell added.