"Construction of the new ramp will unavoidably disrupt traffic flow on the road even more, creating an untenable situation," the statement read.
The federal lawmakers have been asking state and Defense Department officials for additional funding and studies of the site, and they said they would continue to fight for parking restrictions there if the Army fails to adjust the move-in date.
The new proposal still does not address congestion north of the Beltway, said Ron Kirby, a transportation planner for the Metropolitan Washington Council of Governments. The original project included additional roadway capacity and significant increases in bus service into the District, paid for in part by tolls, Kirby said.
"There are some real downsides to this change in terms of capacity to this corridor. No question about it ," he said.
Bob Chase, president of the Northern Virginia Transportation Alliance, said the new project could boost interstate highway travel and job centers outside the Beltway, where most of the region's population growth is expected to occur.
"Arguably, it could work to the detriment of Arlington County's job creation and job growth. It is all about proximity to workforce," Chase said.
The Fairfax County Board of Supervisors previously had not supported any changes to the original HOT lane proposal, board ChairmanSharon Bulova (D) said. But supervisors may support the new proposal because it includes transit service between the Franconia-Springfield Metro station and Tysons Corner, as well as the ramp to the Mark Center, she said.
"The devil is in the details," Bulova said. "We want to make sure we are providing sufficient capacity and traffic flow for commuters coming from the south and from Fairfax County towards the north. We are disappointed the project is not the original project. However, it looks like there is something there we can work with."