A federal judge in Alexandria, ending the latest in a round of court battles that have lasted 15 years, has ruled that state highway officials can proceed with their $37 million plan to widen a section of heavily congested Rte. 1 corridor through Crystal City.

U.S. District Court Judge Albert V. Bryan Jr. lifted late Tuesday an injunction he imposed in 1977 barring any work on the road until the Virginia highway department conducted hearings on the project. South Arlington activists have long contended that the widening of the road would encourage more traffic and noise in an already congested neighborhood.

"I'm ecstatic," said Henry S. Hulme Jr., Arlington's public works chief. "The county as a whole will benefit because it will improve transportation through our most critical area of high density office development, improve traffic management so commuters need not go through the neighborhoods and greatly improve pedestrian access and safety."

Officials of the Virginia Department of Highways and Transportation said yesterday they were excited that they could finally begin the project. But James R. Treese, a lawyer for the Arlington civic groups that fought the work, said they would meet today to decide whether to appeal the decision.

The highway department's plans call for widening from four to six lanes, with turn lanes, a 1.8-mile stretch of Rte. 1 from S. 12th Street in Arlington's Crystal City to just north of Reed Avenue in Alexandria, where a major office complex is proposed.

Opponents in South Arlington have complained bitterly that the road is more like a major highway than the "urban boulevard" concept requested by the county and will only compound traffic congestion, noise and air pollution, and safety problems. Supporters say it should ease traffic on neighborhood streets, and is long overdue.

"Basically, we object to the scale of the road," said Brent Spence, president of the Aurora Highlands Civic Association, which was a plaintiff against the state. "It's not a boulevard. It's not that much different from the interstate road they had planned before."

But the state contends that the new design is radically different from the one originally proposed by the state in 1970. The previous plan, which prompted the suit, called for an elevated highway, I-595, which would have replaced Rte. 1 between I-395 (Shirley Highway) and the National Airport viaduct.

The Arlington Ridge and Aurora Highlands civic associations, joined by two Crystal City hotels, convinced Bryan then that the state had failed to hold the required environmental impact, design and location hearings.

Since then, Bryan noted, the state has "greatly" scaled down the road's plan. The new version has been endorsed by the Arlington County Board and the Alexandria City Council.

Donald M. Wagner, a highway department urban engineer, said yesterday that he does not expect the state to begin the first phase of the project until December. By the year 2000, Wagner said, parts of the road will carry between 40,000 and 45,000 cars a day. Currently, it carries about 32,000.

Leroy Simpson, president of the Arlington Ridge Civic Association, said he expected his organization would have "mixed emotions" about Bryan's ruling.

"In a sense," Simpson said, "it's a step forward in that the project will improve the road and, hopefully, relieve traffic pressures in the neighborhood. But we didn't get everything we wanted . . . in terms of speed control, landscaping and the number of lanes."

"We're disappointed the injunction was lifted," said John Marr, a member of the Center for Urban Education, a third plaintiff in the most recent legal challenge to the road widening plan. " . . . We thought a four-lane highway would have adequately carried the anticipated volume of traffic through Crystal City."