The Fairfax County Board of Supervisors decided unamimously yesterday to keep a 19-year-old promise by rejecting a proposal to extend Fullerton Road west from the Fullerton Industrial Park to Rolling Road.

The controversy, which had been called "a politician's nightmare" by Board Chairman John F. Herrity, was resolved with both sides somewhat satisfied with a compromise plan engineered in committee.

"This is one of those cases, if you look at it realistically and objectively, everyone won," said Marie B. Travesky, Springfield supervisor who led the opposition to the plan to extend the road. "We implemented needed improvements in the area without setting a bad precident."

In 1964 and three times since, the board promised that Fullerton Road would never be extended to largely residential Rolling Road. But Joseph Alexander, Lee District supervisor, asked the board to change its edict citing changing conditions.

Yesterday Alexander expressed some disappointment that the road was not extended, but he said "at least we got the nucleus of it," referring to much-needed improvements.

Rather than put through Fullerton Road, the board decided to rely on other road improvements to allievate traffic problems plaguing the industrial development and surrounding residential areas. The plan would create a normally locked, emergency-access extension of Fullerton Road to Rolling Road.

Although the board closed the book on extending Fullerton Road itself, it adopted as part of the plan a provision that would allow it to consider extending a second road in the industrial park, Boston Boulevard, if the other road improvements do not relieve the traffic situation.