A Fairfax County judge yesterday upheld a law passed by the Virginia General Assembly earlier this year exempting projects in the county's portion of the Route 28 corridor from a December downzoning ordinance.

After four hours of arguments, Circuit Judge William G. Plummer ruled against the county, saying: "I'm not convinced this statute is unconstitutional. I further find that it is not impermissibly retroactive."

About one-fourth of Fairfax's countywide downzoning ordinance was overturned when the General Assembly voted in March to exempt land in the Route 28 Special Transportation Tax District near Dulles International Airport. The tax district also takes in land in Loudoun County, but that was not affected by the Fairfax downzoning.

County officials said the assembly's move was an unprecedented attack on local zoning authority and set a bad precedent for state intervention in such matters.

The Route 28 tax district was created in 1987 to generate additional money for widening that traffic-choked two-lane corridor. Under the agreement setting up the district, property owners there agreed to pay a special tax to fund road improvements.

Fairfax supervisors voted in December to reduce the zoning on more than 14,000 acres, about a fourth of it in the special tax district. Landowners there and elsewhere in the county filed more than 250 lawsuits and sent representatives to Richmond to lobby the General Assembly.

"In one fell swoop, the county was eliminating one of the sources of correcting the {traffic} problems" by reducing the development value of the land in the tax district, said C. Thomas Hicks III, president of the Northern Virginia chapter of the National Association of Industrial and Office Parks.

Keith Boyette, an attorney for Fairfax County, argued that the new state law is unconstitutional because it is special legislation that applies to a specific district. He also argued that the act was an unlawful use of legislative authority because it "puts rezoning powers in the hands of individual developers."

Fairfax Board Chairman Audrey Moore had not yet reviewed the judge's decision, a spokesman said yesterday, and had no comment.