After 14 years of study and debate, the Virginia highway department is on the verge of making major improvements to the heavily travelled portion of Jefferson Davis Highway running south from Crystal City into Alexandria.

A number of hurdles remain, but highway officials say construction may begin as early as next summer.

Before the state turns a spade of dirt on the $37 million, 1.8-mile project, it must first get a federal judge to lift a 1976 injunction barring any work on that section of the highway, U.S. Rte. 1, used by nearly 32,000 vehicles a day.

The state also will have to win approval from the Alexandria City Council and, a state official says, the Arlington County Board, which already is being lobbied by civic groups vehemently opposed to various parts of the proposal.

Alexandria's Del Ray Civic Association wants the improvements to end at the Arlington line.

In the county, civic leaders who are veterans at taking on the state and county on highway and development projects are mobilizing in an effort to get the state to reconsider its positions on everything from road widths and tree locations to sign placements and the speed limit.

The state's current plan calls for widening Rte. 1 from four to six lanes, plus constructing turn lanes, from S. 12th Street in Arlington's Crystal City to just north of Reed Avenue in Alexandria.

It also provides an array of what the state says are much-needed improvements to the neighborhood, including pedestrian bridges and landscaping.

Local civic groups agree that those improvements are long overdue, but argue that other features -- most notably the added lanes -- will exacerbate traffic congestion, noise and air pollution, and safety problems.

The new battle over the highway is an argument some civic leaders concede probably was lost three years ago when Arlington agreed to the six-lane design, although it asked that a four-lane road not be ruled out.

John O'Neill, chairman of the county's transportation commission, said he believes the latest proposals have become a cause celebre because the area already is buffeted by National Airport noise, Crystal City high-rises, planned massive developments at Pentagon City, utility and sewage-treatment facilities and major road networks.

"The neighborhood wants a trophy and the trophy is Rte. 1," said O'Neill, who supports most of the plans for the road. "They've lost every battle about Crystal City. They lost the battle over development of Pentagon City. . . ."

Nancy Swain, a neighborhood activist, disagrees.

"I don't think we've lost everything and Rte. 1 is a trophy just because everyone wants this neighborhood to be a stable urban residential community," she says.

"What we all want is to have the best highway with the least adverse environmental impact on the surrounding neighborhoods as we can get."

Given the history of the state's previous improvement plans, the opposition comes as "no real surprise," said James K. Skeens, an urban engineer for the Virginia Department of Highways and Transportation, which first began drafting Rte. 1 improvements in the late 1960s.

In the early 1970s, the state proposed an I-595 spur from Shirley Highway (I-395) to the National Airport viaduct at the southern tip of Crystal City.

The elevated highway, which would have replaced Rte. 1, was likened to the "Great Wall of China" in a suit brought by Arlington civic groups and two Crystal City hotels.

A federal judge in Alexandria agreed with their contention that the state had held hearings improperly, and he issued an injunction in 1976 barring any work on the road until new location and design hearings were held.

The location hearings were held almost three years ago. The state's design hearings are almost completed, and the two localities still have design hearings coming up next month before they give final approval.

Skeens said he expects the city and county will approve the plans so the department can ask the federal court to lift the injunction in January. If that is done, construction, estimated to take three years, can begin next summer.

State law gives only cities, such as Alexandria, the power to block road projects within their limits. Dayton L. Cook, the city's transportation chief, says the city has endorsed the state's six-lane plan because it is needed to handle traffic that will be generated by a future high-density development on a 40-acre tract between Four Mile Run, the city-county line, and Reed Avenue, where the project terminates.

The fiercest opposition comes from Arlington groups, and Skeens said he doubts the federal court will lift its injunction if the Arlington County Board objects.

However, the state highway department, which battled Arlington groups for more than a decade over I-66, this time has made a point of incorporating almost all of the county's requested changes to Rte. 1 in its current proposal.

"We've done all we could," Skeens said, "except reduce the road."

County Board member Mary Margaret Whipple says she doubts the board will seek to get the number of lanes cut "at this point," and is concentrating instead on design improvements.

Jeff Sikes, a planner for the county's public works department, said the county long ago agreed with state officials that a four-lane plan simply would be insufficient to handle the traffic, expected to increase 40 percent by the year 2000.

"Many, many people in the county are convinced the best approach is a four-lane road," said John Marr of the Arlington Ridge Civic Association, in an opinion shared by Brent Spence of the Aurora Highlands Civic Association. Both concede the state is unlikely to change its plans.

While they advocate a reduction, they and other civic leaders say they are also focusing on the state design features they contend will, in effect, turn the road into a high-speed interstate instead of providing a "people-oriented boulevard concept" with trees on all medians and between the sidewalks and road as the county had requested.