The helicopter rose through the frigid January morning air to reveal a still-life tableau: Thousands of southern Fairfax County commuters, trying to navigate Rte. 1 north through Alexandria, were gridlocked by a new car pool restriction in the city.

In the copter, Alexandria Mayor James P. Moran Jr. didn't say much to Fairfax County Board Chairman Audrey Moore and county Supervisor Gerald Hyland, who had invited him along for the ride. "It looked like a parking lot" on Richmond Highway past Beacon Mall, three miles south of the Alexandria border, Moran recalled.

The next day, Jan. 26, Moran persuaded his City Council to soften the car pool restriction from three occupants per car to two in the Rte. 1 high occupancy vehicle lane during rush hour. The action took place despite city residents' opposition and just a few months before municipal elections.

It was a crucial bow to a sometimes testy neighboring jurisdiction and heralded a year that saw an unusual amount of cooperation on transportation matters within Northern Virginia. Many local officials predict that this spirit will spill over into other issues.

"Nobody ever thought we could get along," Moore said recently.

For just over a year, the elected leaders of the region's local governments have been meeting formally and informally, developing a better understanding of each others' problems and becoming friends in the process. Two late 1987 events jump-started this phenomenon: county board elections for four-year terms in Fairfax, Prince William and Loudoun, and Gov. Gerald L. Baliles' directive that Northern Virginia develop a "subregional" transportation plan.

Moore's triumph over Republican county board chairman John F. Herrity, attributed in large part to voters' anger about Fairfax traffic jams, left Democrats in the top posts in those counties plus Arlington and Alexandria. Baliles' mandate put them and other local leaders to work on a plan to deal with the region's daunting transportation challenges over the next two decades.

The most obvious result is the $10 billion blueprint approved Dec. 16 by a group named, inelegantly, the Subregional Transportation Task Force. The task force plan emphasizes trains, buses and a network of HOV lanes in the effort to forestall gridlock.

Local governments are $7 billion short of the money to implement the plan, prompting pleas to state legislators that jurisdictions here must be given the power to increase several taxes locally. However, tax proposals are particularly tough to sell in an election year, and this is the year in which the governor, lieutenant governor, attorney general and House of Delegates will be elected.

Most elements of the Northern Virginia tax proposal have already run into trouble with key legislators, and many local and state officials say the transportation funding battle will be waged over several years. But local government officials say that even if they don't get much in new taxing power in the upcoming session, the cooperation they have developed will produce results in areas over which local officials have more direct control.

"I'd like to see us tackle drugs and crime" on a regional basis, said Moran, noting that these problems spill over from city streets to suburban neighborhoods. He added that the District's Lorton prison complex should be discussed.

Moore said she has spoken to Democrats and Republicans in some jurisdictions about the possibility of building a regional jail. "We're working together to save money for our constituents," she said.

"There are always economies of scale" that can be accomplished by working with neighboring governments, said Thomas M. Davis III, a Republican member of the Fairfax County Board of Supervisors. Davis said the regional push to solve transportation problems "started when Herrity was chairman," and he added that interjurisdictional cooperation "all comes down to dollars and cents."

"Some of us didn't know each other" in late 1987, just after Moore's victory, noted Arlington County Board Chairman John G. Milliken, whose term as chairman ends in a few days. "The first meeting was more of a social gathering around my dinner table," he said, and sessions have continued in such private settings as well as at public meetings in the development of the transportation plan requested by Baliles.

Loudoun County Board Chairman Betty W. Tatum heads the alliance of top local officials, which became known as the Mayors and Chairs. She commented that its members "have gotten to know each other very well. We've made some important relationships."

She and Moore said that their friendship allowed them to work out an arrangement that will connect Loudoun's Algonkian Parkway with the Fairfax County Parkway (long known as the Springfield Bypass) -- something that officials had failed to accomplish for most of this decade.

Alexandria and Fairfax particularly have a history of animosity, including protracted annexation fights that were finally settled in the legislature. Ten years ago, the city barricaded two local streets at the Fairfax border in the Dowden Terrace neighborhood, which sits on top of the western Alexandria-Fairfax border, to prevent cut-through traffic.

"You wouldn't have a Dowden Terrace today," said Moran.

When Washington Redksins owner Jack Kent Cooke was talking about moving the franchise from the District to Virginia, "We told Cooke as a group that we won't be played one against the other," Moran noted. "When you operate as a unit, obviously you have far more political influence."

The January decision by Moran and the Alexandria council to relent on the Rte. 1 HOV rule is ironic in that the regional plan adopted 11 months later emphasizes HOV lanes with a minimum of four occupants per vehicle on many major highways. Moran says the restriction will work better when it is extended "all the way down Route 1; there's no real incentive to car pool if you're driving 15 miles and only two miles in a car pool lane."

There have been other compromises this year. One of the most controversial involves Ridgefield Road, a proposed major north-south artery in Prince William County and southern Fairfax, which many in Fairfax oppose but which Moore now supports and which the task force plan includes.

The road, planned as four lanes wide in Fairfax and six in Prince William, would connect with the Fairfax County Parkway and divert some rush-hour traffic from bumper-to-bumper I-95. But some people in Fairfax have blasted it as merely a "developer's road" that would overload the bypass, which is now under construction.

Moore said, "Prince William has a tremendous need to go north."

The subregional plan, devised though months of study of technical reports about levels of traffic service, would attempt to keep congestion from getting worse during two decades of phenomenal growth.

The battle in the General Assembly will be just part of the funding war. Vivian E. Watts, state secretary of transportation and public safety, warns that Congress might "step away from the interstate system" and declare it complete. She says Congress should be pushed to increase, not decrease, Northern Virginia's projected $700 million share of federal road funds through 2010.

Local leaders who worked on the $10 billion plan say that they knew from the start something big was needed and that they would have to put their heads together to accomplish it. Still, says William A. Plissner, chairman of the citizen advisory committee of the regional task force, "There was some doubt in my mind whether we would get a plan."