Traffic on southbound I-395 is bumper to bumper in Alexandria headed out of Washington in this November photo. (Alex Brandon/AP)

Construction is underway on the Interstate 95 express lanes, with the new high-occupancy toll road expected to open late next year. But residents living at the northernmost point of the planned lanes are unhappy with the congestion and pollution they say the project will bring.

The express lanes will begin on I-95 in Stafford County and end between Edsall Road and Duke Street on Interstate 395 in Fairfax County, so a ramp must be built to carry vehicles from the new lanes to the regular roadway. That new ramp will be in a neighborhood just west of the Alexandria city line, much to the dismay of residents.

“The environment is going to change dramatically with this project,” said Mary Hasty, 56, who can see traffic on I-395 from her home on Winter View Drive in the Overlook community. “The new ramp will bring congestion up to street level with our houses, 75 feet from our homes and 25 feet from a very popular walking path.”

Hasty, whose husband has respiratory problems, said she is one of hundreds of other residents in her community concerned about the project. They also say that the Virginia Department of Transportation didn’t conduct the necessary studies to determine the ramp’s full impact, opting instead for regional studies.

Steven Titunik, spokesman for VDOT’s mega-projects, said that the agency had conducted extensive studies of the location of the ramp. He also said that the air-quality analysis has undergone thorough environmental reviews.

Residents of the Overlook neighborhood are concerned that an elevated off-ramp at the end of the proposed I-95 HOT lanes will bring dangerously high levels of pollutants into their community.

But residents, contending that no specific local analysis was done, hired an attorney who had successfully challenged the state on behalf of Arlington County. They also commissioned their own privately funded environmental study at a cost of $60,000. It found that placing the ramp there would “increase exposure to harmful pollutants for nearby residents.”

The I-95 express lanes, like the Beltway express lanes that opened on a stretch of Interstate 495 in November, represent a new way to deal with ever-increasing congestion by creating express lanes on which tolls rise to ensure a consistent, congestion-free ride.

The $925 million, 29-mile project is funded by a combination of public and private entities. The state will own and oversee the lanes, while private companies Transurban and Fluor will finance, build and maintain them.

While a ramp between Edsall and Duke has long been part of the plan, it was originally a small auxiliary ramp. After Arlington’s lawsuit prevented the express lanes from stretching into that county, the Landmark ramp became the last part of the HOT lane experience.

Northbound traffic in the express lanes would have to use the new ramp to move into the regular I-395 lanes. Area residents anticipate that those vehicles will slow down, idle and accelerate, spewing pollutants toward their homes.

Supporters of the project say that because cars carrying more than three people and buses can travel for free in the express lanes, the project could ease congestion.

“It takes cars off the road,” said Bob Chase of the Northern Virginia Transportation Alliance. “It’s fewer vehicles and moving more people with fewer vehicles, which is obviously a plus.”

But Stewart Schwartz, executive director of the Coalition for Smarter Growth, said the addition of HOT lanes could draw people out of buses and shared rides and push them into their own cars, particularly in a high-income area like Northern Virginia.

“A lot of people are in these options because the general-purpose traffic is so unbearable,” he said. “But if you’re able to have an efficient commute route and have the income and the willingness to pay for it, you may drive alone more now.”

In addition to exhaust and nitrogen dioxides, the private study warns that the additional traffic will increase fine particulate matter in the air, pollutants that are especially dangerous to those with compromised breathing or other health issues.

The study was conducted from October to December of last year by Maureen Barrett, an environmental engineer who heads the firm Air Expertise Colorado and who has worked on air-quality studies for more than two decades.

Barrett said that the study followed regulatory guidelines and used a model provided by the Environmental Protection Agency to determine how the increased traffic would affect the health and environment of the neighborhood.

Michael Replogle, managing director for policy at the Institute for Transportation and Development Policy, which promotes environmentally sustainable transportation practices, said the study raises credible concerns that local officials should take seriously.

“The citizens group is up against tall odds to block this project,” he said. “But I think they’re raising legitimate issues in a grounded way and deserve to be heard and considered.”

Hasty, who has lived in the neighborhood near I-395 for 11 years, is used to being close to traffic. It’s not just added traffic that worries her and her neighbors.

“It is an EPA requirement that they do an alternatives sites analysis in placing the terminus here. VDOT has not done its due diligence,” said Sue Akubo, another resident activist. “This area is filled with families who have asthma, COPD, heart disease or are cancer survivors.”

The ramp being added is on VDOT property, Titunik said.

“The only impact on the neighborhood would be someone getting off there and getting into the neighborhood,” Titunik said.

Titunik said that if there was any evidence of an error in the air-quality analysis, VDOT would review it and ask the Federal Highway Administration to do the same.

Neighborhood residents are often unhappy about major construction projects. Activists can fight, file lawsuits and contact lawmakers, but it can be an uphill battle.

Greg Smith said he encountered this “unlevel playing field” during years spent unsuccessfully fighting the construction of the Intercounty Connector in Maryland.

“You’re often going up against agencies that have a vested interest in not listening to you,” said Smith , co-director of Community Research, a nonprofit organization that does public outreach and advocacy. “They build highways, and that’s what they do.”