In March 2018, construction of the replacement tunnel was expected to be completed in August 2018, with a planned opening date of October 2018. Cost overruns had reached about $600 million due to the delays in tunnel boring. WSDOT reverted to the tunnel's original opening date of early 2019 to accommodate a longer preparation period and avoid potential work delays due to winter weather. On January 11, 2019, the Alaskan Way Viaduct was permanently closed in preparation for the opening of the new tunnel, which required the excavation of several buried ramps at the south portal and other road realignments.
