SEATTLE (AP) — The troubled project to replace Seattle's Alaskan Way Viaduct with a tunnel faces $223 million in cost overruns.

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 is early 2019.