SEATTLE - The troubled project to replace Seattle's Alaskan Way Viaduct with a tunnel is $223 million over budget.

The Washington state Department of Transportation said Thursday the additional money is needed for the project, originally slated to cost $3.1 billion, because of repeated delays. Those delays have increased the costs of administration and oversight, made it more expensive to acquire the right of way along the tunnel alignment and added to the costs of ultimately demolishing the viaduct.

The Seattle tunnel was the preferred choice to replace the viaduct when it was damaged in a 2001 earthquake. But the tunnel boring machine broke down in late 2013, leading to a more than two-year delay while it was fixed.

The original completion date for the tunnel was the fall of 2015. The latest estimate for the opening of the double-decker highway project was early 2019.

Sen. Curtis King (R-Yakima), the Chair of the Senate Transportation Committee, said increasing toll rates to use the completed tunnel could help offset project overruns.

"The people who benefit from it ought to help pay for it," said King.

His counterpart in the House, Rep. Judy Clibborn (D-Mercer Island), said it was too early to talk specifics, but thought the funding could come from existing state transportation projects.

Clibborn said taxpayers across the state would support paying for completing the tunnel.

"They understand that particular project, more than anything, because Eastern Washington goes right directly through that to get to the port,” Clibborn said. “And they know how important that tunnel is."

Both Clibborn and King agreed the City of Seattle should not have to pay for the overruns, which was a concern when the project was originally approved.