Residents of Longmead Crossing who stepped onto their back porches yesterday morning found their neighbors threading police tape through bamboo stakes topped with yellow balloons.

The message was a protest against the planned intercounty connector: That makeshift fence could soon be a six-lane highway barreling through the quiet, leafy residential area in Silver Spring.

"I didn't realize it was this close," said Pat Johnson, 43, as she gazed at the balloons fluttering atop the stakes a few dozen feet from her yard. A garden hose slung over her shoulder, she had come out onto her patio to clean her pet rabbit's cage. "This disturbs me."

The proposed intercounty connector would be a $1.7 billion, 18-mile toll highway linking Interstates 270 and 95. Proponents warn that without it, suburban Maryland's notorious traffic delays would get worse; opponents counter that the roadway would not alleviate congestion on the Beltway or other major thoroughfares.

Although the connector has been in the works for decades, its exact route has not been determined. Organizers of yesterday's protest sought to inform their neighbors about the proposal that would most affect their community, bifurcating their subdivision and edging up against its soccer field.

Roger Plaut, 38, who chairs the homeowners committee protesting the roadway, said a survey answered by 20 percent of the development's 2,000 households showed that nearly 90 percent of residents oppose the roadway.

"Even if we didn't live so close to the route, we would be adamantly opposed to passing it through existing communities," Plaut said, citing the connector's impact on the environment and state finances.

At the rally, Del. Adrienne A. Mandel (D-Montgomery) called on residents to become "barriers and obstacles" to stop the connector.

"We cannot build roads just to accommodate peak hours," she said. "This project must remain a road not taken -- a road not built."

Critics of the connector say once financing charges are taken into account, the cost would approach $3 billion. Plaut and others favor investing resources in a Metro Purple Line between Silver Spring and Bethesda and in existing roads.

"We need to construct some alternatives to deal with local transportation issues," said Ann Evans, a Longmead resident who suggested using jitney buses to improve access to mass transportation in Montgomery County.

Evans was among dozens of protesters who fanned out into the community of inflatable pools and backyard grills, signs and stakes in hand to demarcate a potential path. "There could be a six-lane highway here," the placards warned.

Fitzroy Scott, 50, was just home from a morning shift when he spotted the sign. "Why do they choose here?" asked Scott, who said the proposed thoroughfare would create a hazard for his daughters and other neighborhood children. "It would be devastating, all the noise and pollution."

Neighbor Joaquin Altamirano said that even if the project improved his commute, he would rather encounter traffic on the Beltway than in his back yard. "It's not logical to put a huge highway behind a residential area like this," he said in Spanish.

As the demonstration wrapped up about noon, Longmead resident Roxanna Weddle pushed in her last stake and headed back to her condo, where she has lived for a decade. Weddle, 52, said she will sell her condo if the connector comes to her neighborhood.

"I moved here because it was out of the way, a lot of trees and a low noise level," Weddle said. "I definitely would not stay."