WASHINGTON – An effort to revive plans for a tunnel to replace the Woodrow Wilson Memorial Bridge was shot down Wednesday by project officials who favor moving ahead with a 12-lane bridge approved three years ago.
A report by the Woodrow Wilson Bridge Project said a 12-lane tunnel would be more costly, would carry less traffic and would be more detrimental to the environment than the proposed replacement bridge.
“The bottom line is that the tunnel raises serious concerns from both an environmental and cost standpoint,” said Gene McCormick, project manager for Potomac Crossing Consultants. “We’re trying to lay out for public record that [a new bridge] is the best decision.”
But the Sierra Club, which has been pushing with other groups for a tunnel since October, said it will ask the Federal Highway Administration for an independent review of a tunnel option.
“We want the tunnel to be given a fair chance,” said Frank Fox, a Sierra Club spokesman. “It is a viable option.”
The current bridge, which carries Interstate 95 over the Potomac River, is old, over capacity and in desperate need of replacement. Project officials, including an FHA administrator who was on hand Wednesday, insist that they gave the tunnel option a fair review, both now and in 1997 when the replacement bridge was chosen as the best plan.
“There are some advantages with a tunnel,” McCormick said. “But the cost increase is significant.”
The report estimates the total cost of a tunnel crossing as high as $3.1 billion, including the cost for necessary approaches and highway interchanges, as opposed to $1.89 billion for a bridge.
But Fox called that cost estimate “completely out of the ballpark.”
He said that Symonds Group, the British firm that would design the tunnel, has estimated that the tunnel would cost $1.2 billion if it were built without the carpool lanes that the bridge plan calls for. Those lanes would require construction of special carpool ramps at the interchanges on both the Maryland and Virginia shores.
“Those interchange ramps are massively expensive and carpool lanes only promote the use of automobiles,” Fox said. “We could save $1 billion by not building [the carpool lanes].”
Instead of carpooling, he said, the tunnel could dedicate those lanes to mass transit, making rail service available from the outset.
“Rail transit is feasible,” Fox said. “We need to do this in an environmentally efficient way.”
But McCormick said the carpool lanes are necessary to accommodate potential high-occupancy vehicle lanes on the Capital Beltway on both sides of the Potomac River.
He said there are other drawbacks to the tunnel, which would not allow for emergency lanes or a pedestrian/bike path planned for the bridge. And even if the tunnel was a wide as the proposed bridge, he said, it could not carry as much traffic.
“Human psychology is to reduce speed in a tunnel,” McCormick said. “Also, in a tunnel you’re restrained from changing lanes.”
The report also questions the technology proposed to build the tunnel. The technology, known as the Immersed Concrete Tunnel Concept, calls for pre- fabricated sections of tunnel to be sunk into a ditch dug into the riverbed.
The report said that technique would result in almost 2 million cubic yards of dredged material from the Potomac, four times more dredge than would have to be disposed of with a bridge.
Fox does not dispute the figure, but he maintains that the tunnel’s “footprint” — the area that would actually have to be dredged — is smaller than a bridge’s footprint and would result in fewer disturbances.
“Symonds Group has done this before and they know what to do,” he said. “The effect will be minimal.”
While Fox is pushing for another review by the feds, FHA project manager John Garner said Wednesday that the tunnel has already been given serious thought. McCormick said the time for study is over and he insisted that bridge construction will begin on time this fall.
“There are no further alternatives,” he said. “We’re going to proceed with the original plan.”