SR 99 tunnel - Complete February 2019

Project overview

The SR 99 tunnel replaced the Alaskan Way Viaduct along Seattle's central waterfront, carrying State Route 99 beneath downtown Seattle. The 2-mile tunnel opened to drivers in February 2019.

Timeline

2009 - 2019

Project status

Completed

Funding

$2.15 Billion

What to expect

The SR 99 Tunnel is open to drivers. The tunnel is a tolled facility with rates changing on a fixed schedule, depending on the time of day. Drivers with Good To Go! passes pay the lowest rates.

Map of downtown Seattle showing the tunnel route stretching from near the Space Needle on the north end to Seattle's sports stadiums on the south end

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The SR 99 tunnel runs between just west of Seattle's sports stadiums and north of downtown near the Space Needle. The tunnel has no mid-tunnel entrances or exits.

History and background

In February 2001, a 6.8 magnitude earthquake struck near Seattle, causing several foundations of the Alaskan Way Viaduct to shift as much as five inches. Engineers believe the viaduct would have collapsed had the earthquake lasted a few moments longer. During the next decade, state and local agencies studied more than 90 alternatives to replace the aging viaduct, which carried SR 99 through Seattle. In 2009, a deep-bored tunnel was chosen. One of the advantages of this option was that it allowed the viaduct, which remained safe for daily use, to remain open during most of tunnel construction.

The tunnel boring machine "Bertha" began digging the SR 99 tunnel in 2013. Bertha completed her dig in 2017 and the tunnel opened to drivers on February 4, 2019.

Milestone

February 2001

Nisqually earthquake damaged the viaduct

2009

State and local leaders agreed to replace the waterfront section of the viaduct with a bored tunnel

2010

Seattle Tunnel Partners was chosen as the design-build contractor to build the SR 99 tunnel

July 30, 2013

Tunneling machine "Bertha"—the world's largest-diameter TBM—began digging the tunnel route

April 4, 2017

Bertha completed tunneling, breaking into the receiving pit near Seattle's Space Needle

January 11, 2019

The Alaskan Way Viaduct closed to vehicles forever as crews begin to realign SR 99 with the new tunnel

February 4, 2019

The SR 99 tunnel opened to vehicles

November 9, 2019

Tolling began on the SR 99 tunnel

The SR 99 tunnel was one of 30 projects that together comprise the Alaskan Way Viaduct Replacement Program.
The budget for the SR 99 tunnel project is $2.15 billion, which included the design-build tunnel, roads that provided north and south access to the tunnel, new streets near the tunnel’s north portal, and the South Access - Surface Street Connections project. Funding came from state, federal and local sources, including the Port of Seattle.
The 2012 Legislature directed WSDOT to toll the SR 99 tunnel to pay back $200 million in bonds that helped finance construction. Tolls also pay for ongoing tunnel operations and maintenance costs, including tunnel safety systems, similar to other toll roads in Washington.
The toll rate is determined by time of day and whether drivers have a Good To Go! pass. Drivers without a Good To Go! account pay an extra $2 per trip. Tolls are higher for vehicles with more than two axles. The toll rates are set by the Washington State Transportation Commission.

SR 99 tunnel - Complete February 2019

Project overview

What to expect

History and background

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