Prince George's County, which has long watched the area's boom in development from the sidelines, is rapidly gaining favor as a commercial building site, according to a summary of 1985 commercial construction compiled by the Metropolitan Washington Council of Governments.

Prince George's gains contrasted with the development picture elsewhere in the Washington area. It and Arlington were the only two of the eight jurisdictions measured that showed gains. Over all, construction dropped 34 percent in the region from the 1984 level.

In Prince George's last year, new commercial development -- including stores, restaurants, offices, hotels and research facilities -- nearly doubled to 4.1 million square feet from 2.2 million the year before.

"Prince George's is seen as an alternative because it doesn't have the glut of other areas," said David Cardwell, a regional planner with the council and an author of the report. "In Tysons Corner, there's only so much land. The same is true for the [Interstate] 270 corridor in Montgomery County."

Although Fairfax County continued to lead the region in the total number of commercial projects, it also experienced the sharpest decline in such development over the previous year, the report said. Compared with 1984, the amount of new commercial construction in Fairfax declined by more than half, to a total of 5.4 million square feet.

In Montgomery County, another traditional leader in the field, commercial construction also was down, with 3.1 million square feet of projects last year, compared with 4.2 million the preceding year.

Montgomery County officials have been wrestling with the problems that accompany rapid development. Last week, the County Council granted itself the authority to limit both residential and commercial construction in areas of the county plagued by "intolerable" traffic congestion, a move that could pave the way for curbs on future growth.

To woo commercial development, Prince George's County officials during the last year advertised in newspapers and national business journals touting "the spaciousness and room to grow" in the county. They also set up a "priority project" system to assure companies interested in locating there of speedy action in obtaining permits and getting applications processed. Currently, the county has 48 priority projects.

"We're in a situation similar to where Fairfax County was eight to 10 years ago, when they started their boom," said Jim Myrtle, business development specialist with the Prince George's County Economic Development Corp. "The image of the county is changing in the eyes of people outside the area because of its strategic location and the available land on the interchanges.

"We like to say we're building a better mousetrap," Myrtle said, "that we're learning from the successes of Fairfax and Montgomery and that we're also learning from their mistakes with traffic and congestion."

In compiling its annual report, the Council of Governments, which serves as the regional planning agency for the metropolitan area, counted a project if ground had been broken or if a developer had contracted for construction during 1985. Only projects worth more than $75,000 were considered.

The 34 percent overall decrease in commercial construction from 1984 is "not necessarily bad news," said COG's Cardwell. "Developers are pacing themselves so they won't develop a bad situation like the one in Houston and Denver where vacancy rates are 25 and 30 percent." The Washington area's average vacancy rate is 10 to 12 percent, he said.

On the other hand, the region's retail construction was one of two building categories to show an increase of square feet under construction in 1985 compared with 1984 -- from 2.9 million to 3.3 million square feet. The hotel/motel category also increased slightly.

Fairfax County officials were quick to point out yesterday that the apparent decline in that county's commercial development does not signify a slip in popularity and, like the figures for the overall region, simply reflects the natural decline that comes after a record year.

"It's all just a function of the construction cycle," said John F. Herrity, chairman of the Fairfax County Board of Supervisors. "A one-year blip, one way or the other, is not a trend and is basically meaningless as a guide. You have to look at the long range, at least 10 years, and during that time, Fairfax has been on top."