The developer of a proposed three-building complex at the southern end of Crystal City agreed yesterday to scale back the project after members of the Arlington County Board expressed unhappiness over the size of the development.

The board opposition "was quite a surprise," said developer William G. Brakefield. "I had no indication" of it, he said after the meeting.

At issue was a proposal by Brakefield's Old Dominion Properties to build an office, hotel and residential project on a triangular piece of land on Jefferson Davis Highway and what is proposed to be S. 27th Street.

The project had received Planning Commission approval, but board Vice Chairman John G. Milliken said the plans called for "too much stuff on too little {a} parcel of land."

In response to the board's concerns, the developer and county planners huddled yesterday afternoon and devised a compromise plan in which the proposed 18-story residential tower would be replaced by a 12-story office tower.

The board took no action on the plan yesterday.

It deferred until Sept. 26 consideration of an 11-story office building and 14-story, 272-room hotel that is unchanged from the original proposal.

The board will consider the rest of the project in November.

Also to be resolved by the board is the request by the developer to cut into a grassy median on Jefferson Davis Highway to provide southbound access to the project.

The two civic associations in the immediate area oppose this, saying the median is part of an agreed-upon highway improvement plan that neighborhood groups worked for 10 years to get.

In other action, the board approved the trial closing of N. Edison and N. 30th streets at Yorktown Boulevard after residents in the area complained that drivers are using their streets as a shortcut, posing safety hazards.

The board also approved a neighborhood conservation plan for the Cherrydale area that emphasizes controlling traffic along Lee Highway and encourages more neighborhood-oriented businesses in the area.