When house shopping last fall, Thomasina Borkman and her husband couldn't pass up the one with a kitchen that opens onto a front deck and a view of thick, peaceful woods.

But the property on Park Vista Court in northern Silver Spring also came with a problem: Those woods are in the path of a proposed route for a six-lane toll highway. If backers of the $3 billion intercounty connector plan have their way, highway traffic -- with all its sounds and smells -- could roar past the couple's house, barely 100 yards away, as soon as 2010.

Borkman said they went ahead with their $500,000 purchase because they don't believe that Maryland Gov. Robert L. Ehrlich Jr. (R) will reach his goal of breaking ground on the highway next year -- or anytime soon.

"I can imagine horrendous noise from the building and traffic tie-ups," said Borkman, 68, a sociology professor at George Mason University. "But if they've been considering this for 40 years, we're just not going to hold our breath. We're gambling, I guess."

Theoretically, real estate agents say, few things make home values plummet like plans for a highway to run through a neighborhood. That theory hasn't taken hold in Montgomery County, where the demand for affordable housing in the increasingly expensive Washington suburbs has caused many buyers to gamble.

As the Maryland State Highway Administration prepares to choose an intercounty connector route in the next several weeks, homes near two possible paths are selling well above asking price, often with multiple offers. Neighborhoods that could be affected by the highway include parts of Rockville, Derwood, northern Silver Spring, Burtonsville, Colesville, Laurel and the Briggs Chaney area.

Some who recently have bought near the proposed connector routes said they do worry about their homes' potential resale values. Still, they point to a beacon of hope: Homes in the shadow of the Capital Beltway, such as in Bethesda, still sell for around $1 million.

Others said they liked the idea of having easy access to an 18-mile highway that would link Interstate 270 in Montgomery to Interstate 95 in Prince George's County, outside the Beltway. And then there are buyers whose real estate agent never mentioned the possibility.

Max Zurita, a paint company sales representative, said he felt so much pressure to buy a home as prices continued to escalate that he didn't have time to research the issue before buying his Silver Spring condominium last month. He said he didn't know he could end up living one street over from the connector until a reporter told him.

"Wow, that's crazy," Zurita, 37, said. "I didn't pay attention. I just didn't want to lose the contract."

The highway proposal has been in Montgomery's master plan for a generation and has endured decades of political wrangling. Even with Ehrlich's backing, it faces big hurdles. Federal environmental officials would have to approve a road that would cut through ecologically sensitive streams, wetlands and other wildlife habitat. Both supporters and opponents anticipate that legal challenges would delay construction if that happens.

Still, home buyers who hope a highway will never materialize should think twice -- or at least research how they might be affected if it does, Maryland transportation officials said.

Sam Raker, who oversees the state's community outreach on the project, noted that Ehrlich has made building a connector his top transportation priority. The General Assembly recently approved the highway's financing plan.

"It's made major steps towards becoming a reality," Raker said. "I personally would not bet against a road being built at this time."

Unlike a history of a leaky roof or wet basement, home sellers and their agents aren't required to disclose the proximity of a potential highway, real estate agents said. It's up to buyers or their representatives to know about it or to research it in the county's master plan or the state's environmental impact study.

Real estate agent Victor Llewellyn said he recommends that prospective buyers check the planned routes for the connector before he sells them a home nearby. He said he sold a home two months ago in Norbeck Estates in Rockville for $57,000 above the asking price.

"It had no impact whatsoever," Llewellyn said, "and that was literally six houses from where the ICC would be coming."

Some recent buyers said they presume sound walls or trees would buffer the noise and obscure the view -- assumptions state highway officials say are not always accurate.

Neil J. Pedersen, Maryland's highway administrator, said the state has tried to minimize impacts on neighborhoods. Plans call for sound walls along eight to 16 miles of the 18-mile road, depending on the path chosen. The road would be sunken where topography allows, which could make it quieter and less visible, Pedersen said. It would have to be elevated over wetlands and streams.

Beth Gatti, 35, a freelance editor and writer who works from home, said she and her husband, Jon, knew the connector could run behind the townhouse they bought in October in the Longmead Crossing subdivision in Silver Spring. But the neighborhood seemed great for children, Beth Gatti said, and it's convenient for her husband's commute to Bethesda and the District.

She said they hoped that, even if plans for a highway went through, court fights would delay its construction until they moved. She and her 2-year-old son suffer from asthma, she said, and they couldn't endure the vehicle pollution.

As first-time home buyers, Gatti said, they couldn't pass up the $340,000 price tag.

"You get squeezed because housing prices are so out of control, and we didn't want to have to move way out to Centreville or Frederick," Gatti said. "We felt extremely lucky we were able to afford something this close to D.C., so it was a gamble we were willing to take."

Some buyers can't envision where a highway would go or what it would be like to live near one, said Dave Savercool, a real estate agent.

"Would it be below grade or would there be sound walls or a buffer?" Savercool said. "Those are the things people don't know now."

Greg Smith, who has been involved in a campaign against the intercounty connector, said he is concerned that even people who wade through the "huge data dumps" in the state's voluminous draft environmental impact study won't learn enough about the possible health risks of living amid highway pollution.

"Some people may be buying their home without knowing the real potential impacts," Smith said. "If they did know, they might not buy that home, given a choice."

Database editor Dan Keating contributed to this report.

Thomasina Borkman and her husband bought a home in the woods last year knowing a highway could be built nearby.

Thomasina Borkman says she and her husband doubt a highway will be built soon: "If they've been considering this for 40 years, we're just not going to hold our breath."