A traffic disaster is coming to Northern Virginia in just over a year when an additional 18,000 commuters added by military job shifts jam area roads, say officials who are scrambling to mitigate the gridlock.

The Defense Department is moving thousands of jobs from Crystal City and the Pentagon to Alexandria's Mark Center and Fort Belvoir and its Engineer Proving Ground in Fairfax County.

"It's going to be absolute chaos," said U.S. Rep. Jim Moran, D-Va., who represents the area. "I think it's just going to be awful."

Officials around the Washington region have been scrambling for years to handle the military job shift. But on Tuesday, Virginia transportation executives conceded that road improvements around the Mark Center -- a major part of the military expansion -- are at least four to five years away.

Montgomery County is facing traffic woes when Walter Reed Hospital is merged into the National Naval Medical Center in Bethesda, promising slow commutes on such major thoroughfares as Route 355 and Connecticut Avenue. County officials are scheduled to discuss options for the site on Thursday.

After years of talks and hundreds of thousands of dollars spent on studies since the Pentagon's base realignment schedule was published in 2005, officials are still searching for feasible solutions.

An example of the challenges ahead: The Mark Center, which will house 6,400 defense workers, is not near a Metro station and does not have direct access to Interstate 395, promising horrid commutes until a solution is found.

"It's going to give an altogether new meaning to 'gridlock,' " AAA Mid-Atlantic spokesman John Townsend said. "It may have been one of the most ill-conceived plans in the world."

The Virginia Department of Transportation says there will be "complete gridlock" on Seminary Road and Beauregard Street and "severe" congestion between the King Street and Duke Street exits on I-395.

"It represents the worst kind of planning in a century," said Greater Washington writer David Alpert.

Severe congestion at the Engineer Proving Ground just off the Fairfax County Parkway would last three to four hours each morning, according to an Army Corps of Engineers study. Traffic waiting to get on base at Fort Belvoir would back up onto I-95 and extend the morning rush another one to two hours.

Some partial solutions are planned, or under way. Route 1 is being expanded to relieve congestion at Fort Belvoir, and Moran has fought for some $150 million in federal help. Planners are weighing express bus routes, special access roads and restrictive parking measures to encourage carpooling.

The Pentagon didn't want to talk about the moves. But some people, such as real estate agent Cindy Jones, were looking at the bright side of the influx of workers.

"I do think it's a great opportunity for the south county, particularly the Occoquan River communities. You're going to have a lot of people who ... need to eat, they need to go shopping," she said.

Alexandria resident Don Buch, who lives near the Mark Center, said he's disgusted with area leaders.

"Quite frankly, they blow a lot of smoke. And I understand that they're politicians and they're not going to hang themselves in public," he said. "At the same time, you can't get a straight answer."