Washington State Route 99 closed in Seattle for tunnel alignment; crews making good progress

With the closure this week of State Route 99 in Seattle for tunnel work, construction crews are on schedule with good weather, including unusually warm daytime temperatures in Puget Sound.

So that crews could realign SR 99 to a new tunnel, the Alaskan Way Viaduct was shut down from South Spokane Street to the south end of the Battery Street Tunnel, according to the Washington State Department of Transportation (WSDOT).

The SR 99 Alaskan Way Viaduct – an elevated concrete structure built in the 1950s – is being replaced with the 1.7-mile tunnel running beneath downtown Seattle.

Replacing the viaduct with a tunnel allows the highway to remain open for much of construction, minimizing closures and impacts to traffic. Once the tunnel opens, the viaduct will be taken down to clear the way for new public space along Seattle’s downtown waterfront.