A July 13 article about the Woodrow Wilson Bridge misstated the distance involved in the lane reductions on the outer loop of the Capital Beltway this weekend. The outer loop will be reduced to one lane for about a mile, not six miles, on the Virginia side of the bridge. Also, the article said a ramp to Church Street would close for three years starting this weekend. It will close for three years within the next month. (Published 7/14/2005)

The biggest traffic jam likely to occur during the 11-year construction of a new Woodrow Wilson Bridge will begin this Friday night and last the entire weekend while workers realign a section of the Capital Beltway, project managers said yesterday.

Lane closures and detours could back up northbound traffic on Interstate 95 in Virginia for 15 miles. They will be in place from 8 p.m. Friday to 5 a.m. Monday while workers lay asphalt for the realigned highway section near the western end of what will become a 12-lane bridge across the Potomac River.

Sustained rains or extreme heat could interfere with the work schedule. A final decision on whether to go ahead will be made about 6 p.m. Friday, project officials said.

During the paving, the Beltway's outer loop will be reduced to one lane from the river to Springfield, backing up traffic for at least that six-mile stretch.

But the worst of the backups probably will stretch south from Springfield, where cars heading to I-95 will be diverted to prevent tens of thousands of motorists from heading toward the old bridge, scheduled to close in 2006, when the first of the replacement spans is complete.

If the closures take place, normally moderate delays will turn monumental, project officials said. Delays could last as long as 90 minutes and considerably longer if there is a fender bender or other problem.

A second set of traffic-stopping weekend-long closures is scheduled to occur within the next month for similar work on the inner loop.

The Beltway realignment will clear room for workers to complete an overpass at South Washington Street in Alexandria, one of the many phases of what is now the biggest and most expensive construction project on the East Coast, and one that is rapidly moving toward completion of its major goals.

But the reverberations from cutting off two major arteries this weekend will cascade across the Washington region as well as the East Coast as local and long-distance drivers are forced to alternate routes. Traffic is likely to surge on the western portion of the Beltway crossing the American Legion Bridge and Interstate 395 heading into Washington. Officials also expect increased traffic on Route 301 through Southern Maryland as motorists look for other ways to get around the area.

Project officials said they also expect local roads across Northern Virginia to be overwhelmed, as some are used for detours and others are jammed by drivers looking for their own escape routes. Local drivers will have trouble getting to Beltway interchanges between Springfield and the bridge.

"Our core message is, 'Stay away if you can,' " said John Undeland, Wilson Bridge project spokesman.

The new, $2.43 billion bridge will replace an aging span that is crumbling under the strain of carrying nearly 200,000 vehicles a day, considerably more than the 75,000 it was built to handle.

The structures will have eight general-use lanes to match the number feeding from the Beltway, plus one transit lane and one merge lane on each side. Several interchanges in Virginia and Maryland also will be upgraded to increase capacity on the Beltway and to accommodate the additional lanes on the bridge. Most of those projects will be finished by the time the second of the two new span opens, although improvements to the Route 1 interchange will not be completed until the middle of 2009, and the Telegraph Road interchange will not be finished until late 2011.

A casualty of the next phase of construction is the ramp from the inner loop to Church Street in Alexandria, which will close this weekend for the next three years to accommodate Beltway widening.

This weekend's closures will provide a 57-hour window for highway workers to lay asphalt between the outer loop and the new lanes.

The realigned section is a slight, banked turn that requires laying up to 24 inches of asphalt. About two to three inches of asphalt can be laid at a time. When it hits the ground, it has a temperature of about 300 degrees and must cool to about 130 to 150 degrees before another layer can be added.

That takes time, project officials said, and the highway cannot be opened while the asphalt cools. Project officials said they also need to close two Beltway lanes to stage equipment and to serve as a safety buffer for workers and drivers.

Project managers chose to do the work over the weekend because there are fewer drivers and fewer peak periods on Saturdays and Sundays. On a typical weekday, about 91,000 drivers are on the outer loop, compared with about 72,000 during weekends.

Nonetheless, highway users are expecting significant pain. Mike Russell, spokesman for the American Trucking Associations said concerns about potential delays are so severe that they are sending messages across the nation warning truckers away from the area.

"Hopefully, having this much lead time, they can adjust accordingly," Russell said.

Project officials said they are spending $350,000 this summer to alert drivers via e-mail, radio, newspaper and other mediums about the expected delays. Undeland said radio ads are playing in Richmond and the Tidewater area and as far south as the Outer Banks of North Carolina in an effort to scare drivers from the area.

Project officials also said they are adding extra tow trucks, safety vehicles and other incident response equipment so an accident or another problem doesn't further delay workers or motorists.

A spokesman for the Springfield Interchange project said there also could be weekend work there, but it probably would not add to delays.

Traffic will be rerouted on the Route 1 interchange of the Beltway this weekend.Closures and detours around the Route 1 interchange on 495 are expected to delay traffic as much as 90 minutes.