An extension of the Mid-County Highway in Montgomery County probably will never be built, county lawmakers predict.

Under study for nearly a decade, the project would build a highway from Gaithersburg through Montgomery Village to Clarksburg.

The latest estimate prices the project at roughly $260 million, give or take 10 percent, according to Edgar Gonzalez, deputy director for transportation policy in the Montgomery County Department of Transportation. Final numbers will be available when the study is completed in June.

The price tag and the potential environmental impact of a highway cutting through wetlands have given some Montgomery County lawmakers reason to doubt that the project will ever be built.

"I've come to the conclusion that it isn't going to happen," said Councilman George Leventhal, D-at large.

With no state or federal money available to pay for transportation projects and with several hundred million dollars' worth of county transportation projects waiting to be completed, it's unlikely the county will be able to afford the road for decades, he said. "We ought to stop pretending that it's going to happen."

Environmentally, the project has its origins in an "old school" thought process, said Councilman Hans Riemer, D-at large. "They were dreamed up when people thought the best place to put a highway was above a stream."

Though the project has some supporters, most of the County Council would be unlikely to support it given those concerns, said Councilman Phil Andrews, D-Gaithersburg/Rockville. "There are multiple county road and transit projects that are a higher priority to a majority of council members than a Mid-County Highway."

The highway has been unpopular with residents, especially those in Montgomery Village, who have flooded planners and lawmakers with requests that they reroute the project or drop it altogether.

"We're at the beginning of that road, and it will destroy the environment that we bought for here," said Marie Van Wyk, board of directors secretary of the Christopher Court Condominiums in Montgomery Village. "We have a nice stream down there that's going to be paved over. We have deer occasionally. We have foxes. All of those animals are not going to be around."

But the highway has been in the county master plan since the 1960s, supporters argue, and would be an important way to lighten traffic that has grown increasingly worse.

"If they don't build [the highway], they have to build other things, like add additional lanes [to roads] in the [Agricultural] Reserve," said Councilwoman Nancy Floreen, D-at large. "The whole point is to add a way for people in the Up-County to get around."

Riemer suggested the county consider transit alternatives. But transit is unrealistic in the upper county, Floreen said.

"It's unrealistic to think that everyone in the up-county is going to take the bus. Period."