Local Information

SR 99 tunnel to open in early 2019, but not before the longest highway closure in Puget Sound history

Monday, September 17, 2018 - 09:06

Laura Newborn, Alaskan Way Viaduct Replacement Program communications,
206-805-2871; 206-639-8577 (mobile)

SEATTLE – Mark your calendars. In early 2019, the new State Route 99 tunnel will open, offering travelers a direct route from Seattle’s stadiums to the Space Needle. 

To open the tunnel, the Washington State Department of Transportation must first realign the state highway, and then move SR 99 from the seismically vulnerable Alaskan Way Viaduct into the tunnel. This intensive work will last about three weeks and prompt the longest major highway closure to ever hit the Puget Sound region.

“The opening of the SR 99 tunnel will be an historic event in the state’s transportation history,” said Brian Nielsen, administrator of the Alaskan Way Viaduct Replacement Program. “Before we can celebrate, we have to get through an unprecedented closure that will require all of us to change our behavior.”

WSDOT’s current plan is to close SR 99 through Seattle beginning Friday, Jan. 11, 2019. Closing SR 99 through Seattle is the only way crews can finish building the highway and the eight new ramps that will allow travelers to enter and exit the new tunnel.

Travelers should expect region-wide congestion for up to six weeks as crews complete final connections to and from the new tunnel. In addition to the three-week closure: 

  • The off-ramp from southbound SR 99 to South Atlantic Street will permanently close one week earlier than the viaduct.
  • The new off-ramp from northbound SR 99 to South Dearborn Street will require up to two weeks of additional work after the tunnel opens.

Get ready, make a plan (pdf 494 kb)

When the viaduct closes, 90,000 drivers who normally use the Alaskan Way Viaduct will need to find another way to get to, or through, downtown Seattle.  During past Alaskan Way Viaduct closures, congestion increased on all major highways throughout Puget Sound as well as on local streets. 

While WSDOT is working closely with the Seattle Department of Transportation, King County Metro and other key transportation agencies to keep traffic moving during this challenging time, help from drivers is critical.

“We need drivers to change their habits for three weeks to prevent gridlock,” said Nielsen. “We recognize everyone’s strategies will be different based on their needs, but consider other ways to get to and from your destination, if you can.” 

Closure timing

When Seattle Tunnel Partners finished disassembling the tunneling machine Bertha in 2017, WSDOT estimated the tunnel would be open in early 2019. While there was optimism this date could be moved up, a number of factors influenced the decision to stay with the early 2019 date:

  • Construction progress: WSDOT has several contractors that must complete work to be ready for the three-week SR 99 closure. Scarsella Brothers, Inc. will then build the final tunnel and ramp connections. Some of this work, like road striping, is weather dependent.
  • Public notice: Starting in January ensures that contractor work will be complete and we can provide a specific date much further in advance. The public’s help will be critical and this will give everyone time to plan.
  • Holiday travel and commerce: WSDOT and its partner agencies are committed to keeping people and goods moving during the busy holiday season. Avoiding a major highway closure between Thanksgiving and New Year’s Day helps achieve this goal. There are also fewer major events in early 2019 than there are during the last quarter of 2018.

Per the Legislature’s decision, the SR 99 tunnel will be tolled as a part of the project’s financing plan. The tunnel will be free to use when it first opens.

Additional details about the closure, tunnel opening and the future tolling of the tunnel can be found at www.99tunnel.com

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