Current Status (as of 04 FEBRUARY 2019):TUNNEL OPEN ... ENJOY!
Alaskan Way Viaduct Replacement ProgramIn summer 2013, the world’s largest-diameter tunneling machine began a historic journey beneath downtown Seattle. Its purpose: dig a tunnel to replace the SR 99 Alaskan Way Viaduct, a double-deck highway that has spanned the downtown waterfront for more than 60 years.
The machine’s task sounds straightforward enough, but the story behind it is complicated. It begins with an earthquake in 2001 that damaged the viaduct and led to a decade of debate about how to replace the structure. The story's conclusion is unfolding now, as we at the Washington State Department of Transportation, along with our agency partners, build a new SR 99 corridor through Seattle that includes:
- A
two-mile-long tunnel beneath downtown Seattle.
- A mile-long stretch of new highway that connects to the south entrance of the tunnel, near Seattle’s stadiums.
- A
new overpass at the south end of downtown that allows traffic to bypass train blockages near Seattle’s busiest port terminal.
- Demolition of the viaduct’s downtown waterfront section.
- A
new Alaskan Way surface street along the waterfront that connects SR 99 to downtown.
The tunnel will change the way traffic uses SR 99 in Seattle. Drivers approaching the tunnel from either direction will face a choice depending on their destination: use the tunnel to bypass downtown or exit to city streets and head into downtown. At the
tunnel’s north end, downtown access will be similar to today, with on- and off-ramps near Seattle Center.
From the south, new on- and off-ramps will connect SR 99 to downtown via the new waterfront street.
Halfway ThereHalf of the viaduct is already gone,
demolished and replaced by our crews at the south end of downtown, near Seattle’s stadiums. Completed on
budget and one year ahead of
schedule, this new section of SR 99 connects to the remaining viaduct along the waterfront to keep SR 99 traffic moving until the tunnel opens in
2016 2017 2018 2019.
Related ProjectsAs part of the Alaskan Way Viaduct Replacement Program, King County, City of Seattle and the Port of Seattle are planning
street, transit and
waterfront improvements. Click on the related projects map above to learn more.
Waterfront Improvements:The
Waterfront Seattle website has many images, links, and plans that may be of interest.
PhotosFinal Design:

South Portal:

North Portal:

Bertha, seen before she was put together:
Waterfront Plans

