Alaskan Way Viaduct Replacement Program

Program overview

The Alaskan Way Viaduct, an elevated section of State Route 99 in Seattle, was built in the 1950s, and decades of daily wear and tear took a toll on the structure. The structure was weaked in the 2001 Nisqually earthquake, requiring emergency repairs. Because of the viaduct’s age and vulnerability to earthquakes, replacing it was critical to public safety.
The Alaskan Way Viaduct Replacement Program includes 30 projects led by the Washington State Department of Transportation, King County, the City of Seattle and the Port of Seattle. The Federal Highway Administration is a partner in this effort. Major elements of the program include:

Projects and schedule

The Alaskan Way Viaduct Replacement Program is made up of 30 different projects, the first of which was completed in 2008 (pdf 327 kb).

Photos and video


Anyone interested in obtaining environmental permitting documents related to the Alaskan Way Viaduct Replacement Program can request them by emailing We are in the process of a website update, and the new website will contain direct links to those files.

Budget and funding

The state's viaduct replacement projects are estimated to cost $3.35 billion. Funding comes from state, federal and local sources, as well as the Port of Seattle and tolls. In June 2020, the program received an additional $25 million in the 2020 Supplemental Budget with which to deliver the remaining program work.

State projects Project status Budget ($M)
SR 99 Tunnel Project (includes design-build project, North and South Access contracts) Construction $2,145.6
SR 99 South Holgate Street to South King Street Project (includes Stages 1, 2 and 3) Complete $347.7
Central Waterfront Viaduct Removal and New Alaskan Way Construction $366.2
Central Waterfront Construction Mitigation (parking and mitigation) Complete $24.5
Other Moving Forward Projects Complete $171.3
Program Management -- $131.0
Prior Environmental Impact Statements, Right of Way and Design Costs -- $163.7
Total budget   $3,350.1
State funding Funding ($M)
2005 Gas Tax (Partnership Funding) $1,695.4
2003 Gas Tax (Nickel Funding) $326.4
Other State $4.8
Federal $787.2
Local $68.6
Toll $200.0
Port of Seattle $267.7
Total Source of Funds $3,350.1