It isn’t over until it’s over, but the two-decade battle over a three-quarter-mile stretch of D.C. road is now closer to over than ever.

A federal judge has dismissed a lawsuit challenging the decision to formally close a portion of Klingle Road NW to traffic, ending the last serious bid to reopen a street connection across Rock Creek Park that has been severed since a 1990 sewer collapse.

“It’s not looking hopeful,” said Gale B. Black, a Crestwood advisory neighborhood commissioner who was among the plaintiffs in the lawsuit that sought to reopen the road.

Plans to convert the corridor into a hiker-biker trail, however, are at least three years from completion, and the cost has ballooned since the D.C. Council ordered the change in 2008.

The District transportation department has started planning the trail, a process expected to take another year, spokeswoman Monica Hernandez said. The project is estimated to cost $8 million to $11 million and will include new storm sewers and environmental work.

Hernandez said the city has identified $6 million in federal highway money to fund the work in the fiscal year that begins in October. An additional $3 million was included in the recently passed city budget for future work, and more money is being sought for stream-restoration work.

The costs now expected for the trail are about five times higher than those discussed four years ago, when the council reversed a 2003 vote to rebuild the road.

That followed years of high-pitched controversy that pitted road users, many in less affluent neighborhoods east of the park, against environmentalists and well-to-do residents west of the park — including late NBC News host Tim Russert, who owned a home in Woodley Park near the western end of the closed stretch of road.

Council member Mary M. Cheh (D-Ward 3), who engineered the move to create the trail, said the court ruling means “fingers crossed, this is the end.”

Other obstacles to completing the trail have already been hurdled. In March 2011, authorities completed an environmental assessment that determined converting the decrepit road into a trail would have no meaningful impact. The lawsuit, in part, challenged that assessment.

U.S. District Judge James E. Boasburg ruled Aug. 9 that the activists, who sued various District and federal officials, had chosen the wrong targets for their complaint.

“The D.C. Council, rather than any of these Defendants, closed Klingle Road,” he wrote, adding that the plaintiffs’ quarrel “lies with the actions taken by those elected representatives. If they seek relief, that is where they must direct their efforts.”

Black, the lawsuit’s lead plaintiff, said she had not discussed further options with her fellow litigants but agreed that road proponents’ legal options are dwindling.

“To be honest, I think I’m not inclined to pursue this in the courts,” she said. “We thought we at least needed to challenge this particular precedent of closing this road thousands used and converting it into essentially a dog park.”

Eleanor Oliver, a co-plaintiff and longtime Cleveland Park resident, said she’s still willing to fight against what she called “a little vasectomy” to the city transportation network.

“I think there are further legal options,” she said. “But perhaps the judge is right — go back to the council.. . . We’re going to get so choked with traffic they’re going to have to open it up.”

But Jim Dougherty, a local Sierra Club activist and a veteran of the Klingle wars, noted the road has been closed for two decades with little ill effect on auto mobility. He also said that Mayor Vincent C. Gray (D), Council Chairman Phil Mendelson (D) and most council members remain in favor of building the trail.

“The basic question here is resolved,” he said. “Now it’s a question of execution.”