Seattle's State Route 99 Tunnel opens to traffic on February 4, 2019.

  • By Casey McNerthney
  • Posted 1/10/2020
  • Essay 20945
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At 12:17 a.m. on Monday, February 4, 2019, the State Route 99 tunnel replacing the Alaskan Way Viaduct opens to traffic. The 1.7-mile route under downtown Seattle is North America's largest bored tunnel, stretching from the South Lake Union neighborhood at its north portal to the Sodo neighborhood at its south end. The $3.374 billion project is completed after years of delays, cost overruns, and concerns about the potential for damage from a major earthquake, heightened by a 2009 simulation showing how the viaduct could collapse in a 7.0 magnitude quake. A month after the tunnel opens, it averages more than 70,000 daily weekday trips, with nearly 500,000 vehicles passing through it weekly. By November 2019, tolls are in place, the last viaduct piece is down, and the tunnel is part of Seattle's daily commute. 

Leadup to the Tunnel

Perhaps no road in Seattle was more debated than the Alaskan Way Viaduct and its potential replacement. An elevated roadway was first suggested in 1910. Federal funding and a traffic study in 1947 helped make the viaduct and what became Interstate 5 a reality, though even then there were calls for a tunnel instead of the viaduct. Those calls echoed similar suggestions from 1912 and 1916. The viaduct officially opened on April 4, 1953, and was completed in 1966 with eight ramps and two underpasses. But the desire to replace it continued for decades, and that conversation intensified in 2001 after the 6.8-magnitude Nisqually Earthquake caused irreparable damage.

In January 2008, state leaders wanted a $2.8 billion elevated highway, which would have offered more lanes than a tunnel. King County Executive Ron Sims wanted a surface-street solution, and Seattle Mayor Greg Nickels advocated for a tunnel. Governor Chris Gregoire said if there was still debate in 2012 about the replacement, people could watch her tear the viaduct down. In 2009, state, city and county leaders agreed on a tunnel, and on May 12, 2009, Gregoire signed Senate Bill 5768, authorizing $2.8 billion in state funds for the project.

The ceremonial groundbreaking was held June 6, 2012, though then-Seattle Mayor Mike McGinn, who opposed the tunnel, didn't attend. Nickels, Gregoire, King County Executive Dow Constantine, City Councilman Tom Rasmussen, McGinn's transportation director, Peter Hahn, and others did attend. Bertha, the deep-bore drilling machine made by Japan's Hitachi Zosen Sakai Works and named for former Seattle Mayor Bertha Knight Landes, arrived in April 2013. Drilling began near Safeco Field the afternoon of Tuesday, July 30, 2013, and was initially expected to be done in 14 months.

The tunnel contract required that the roadway be driveable by May 2016. But there were over-heating issues with Bertha that December, and in January 2014 Bertha hit an 8-inch-wide, 119-foot-long steel pipe abandoned by the Washington State Department of Transportation from an earlier groundwater study. A month later, WSDOT announced that Bertha's seals were damaged, and the overheating problems continued. That December, a crack was discovered at S King Street and First Avenue S, and a map released by state transportation officials showed many Pioneer Square areas near Bertha's 120-foot pit sank an inch or more.

Bertha hadn't moved by October 2015 when WSDOT filed a lawsuit against the contractor, Seattle Tunnel Partners. It finally resumed digging in December 2015, but stopped shortly after due to a broken part, and then stopped again because of a sinkhole. After other stoppages, Bertha reached the one-mile mark in November 2016, though the drilling machine stopped again the following March because it was 6 inches off alignment.

Bertha reached its final destination on April 4, 2017, breaking through around 11:30 a.m. near Sixth Avenue N and Thomas Street. "This is a historic moment in our state's transportation history," Governor Jay Inslee said. "Innovation and perseverance are the engines that keep Washington in the forefront. There is still more work ahead but this moment is one worth celebrating" (Bertha's Breakthrough ...").

Viaduct Closure, Tunnel Walkthrough

The Alaskan Way Viaduct was scheduled for a 10 p.m. closure on Friday, January 11, 2019. But the hundreds of cars trying to be the last across the viaduct caused a massive traffic backup. Some even stopped, shared drinks and blasted music, while other cars did doughnuts on the viaduct well after the 10 p.m. deadline. A Subaru Outback was expected to be the last car until the State Patrol pushed a stalled vehicle -- the last public car to drive on the viaduct -- down the northbound exit ramp before the Battery Street Tunnel at 11:38 p.m.

During the following three weeks when the viaduct was closed and the tunnel had yet to open, WSDOT crews worked on the Realign 99 project, getting ramps and roads ready for the new configuration. Media reports predicted traffic "viadoom," and TV news had team coverage with helicopters overhead for the first closure days. Even WSDOT advised people to stay home, warning that traffic would worsen considerably. But viadoom didn't come, and traffic didn't seem much worse than a normal weekday commute.

People on foot were the first to experience the 1.7-mile tunnel. On February 2, two days before the official opening, an estimated 99,000 people celebrated the tunnel's opening and the viaduct's farewell. It started with roughly 29,000 people running a 7:30 a.m. 8K through the tunnel. Then officials cut a ribbon near the south portal for the 11:30 a.m. ceremonial opening. The public then had the chance to walk the tunnel and viaduct, all together or in part. Time-stamped tickets were promoted weeks ahead of time through WSDOT's website, but most of the 75,000 free tickets claimed weren't checked at the event. It was more an effort in crowd control, with walkers allowed in the tunnel and on the viaduct beginning at 12:30 p.m. There were science, technology, engineering and math displays at the tunnel entrances and live music and food trucks on the viaduct, which allowed walkers until 6:30 p.m.

The events concluded February 3, a Sunday, with the Cascade Bicycle Club-sponsored 12.5-mile bike ride through the tunnel and onto the viaduct -- an event packed to capacity with 12,500 riders registered. As Inslee said, it was a once-in-a-lifetime opportunity for Washingtonians "to celebrate the vision and innovation that is helping us plan and develop our region's future" ("Gov. Inslee To Cut Ribbon ...").

The tunnel was scheduled to open in early February, but it was announced it would open earlier than expected in time for the morning commute on Monday, February 4. At 11:15 p.m. on February 3, WSDOT tweeted that the northbound tunnel lanes were officially open, and crews were working to open the southbound lanes. Both directions were open by 12:17 a.m., with ramps open five minutes later. That morning, the tunnel opening was a top story, though weather dominated the news headlines. A rare snow event hit Western Washington beginning Sunday afternoon, causing school delays and closures. The snow and the new road configuration led to confusion: drivers weren't quite sure how to exit southbound near the stadiums. February 2019 became the snowiest Seattle month in a half century with 20.2 inches -- including 14.1 inches in the month's first 10 days.

Inside the Tunnel

The tunnel had no downtown exits, and none were planned, though drivers could leave State Route 99 on new interchanges ahead of the tunnel portals. Before the viaduct closed, roughly 25,000 cars took the Seneca-Columbia downtown exits daily, and bus routes that carried another 25,000 or more people were shifted to the waterfront bus lanes along the rebuilt Alaskan Way South.

The 32-foot-wide tunnel had two 11-foot southbound lanes on the upper deck and two 11-foot northbound lanes on the lower deck, with an 8-foot shoulder on the waterfront side of each. The speed limit was set at 45 mph during regular traffic, though electronic signs allowed for lower limits during heavy traffic. Overhead clearance was 15 feet, 9 inches below traffic signs. Metro buses that used the viaduct shifted to surface streets.

The tunnel had sprinklers, hazardous materials were prohibited, and ventilation systems were designed to remove smoke from crashes inside -- and also to activate if high carbon monoxide levels were detected. Emergency exits led to protected passageways, with green marks along the tunnel walks showing the distance in feet to each exit. The tunnel was designed to withstand a 9.0 earthquake and to pump 1,090 gallons of water per minute with an emergency storage of 480,000 gallons. 

On February 19 -- 15 days after the tunnel opened -- a new northbound State Route 99 offramp opened before the morning commute near CenturyLink Field and T-Mobile Park. The new exit led drivers to an intersection at S Dearborn Street where they could go straight to Alaskan Way and the waterfront, or go right for First Avenue to reach downtown and Sodo. WSDOT announced the ramp was the first in the world built with flexible metals and bendable concrete designed to sway in an earthquake.

Viaduct Disappears, Tunnel Lawsuit Continues

Demolition of the Alaskan Way Viaduct, done by Kewit Infrastructure West Co., started on February 15. Inslee took the ceremonial first chunk, saying Seattle won the race against time. Seattle mayor Jenny Durkan called it a big step toward building the city's future with 20 acres of public space. The Battery Street Tunnel, which closed to traffic on February 1 was filled with the viaduct's crushed concrete. The final piece of the viaduct, a north-end column near the Pike Place Market, hit the ground at 11:20 a.m. on November 21, 2019.

Tunnel tolls started on Saturday, November 9. Drivers with a Good To Go pass -- the same passes used for the State Route 520 bridge, the 405 Express Toll Lanes and the Tacoma Narrows Bridge -- paid between $1 and $2.25 one way. Rates for drivers without a pass ranged from $3 one way on weekends to $4.25 one way during the afternoon commute. Tolls for drivers without a pass were billed by mail. As of January 2019, the total marketing budget for the SR 99 tunnel was $4.4 million, including $156,000 spent on nine billboards with the message "tunnel direct" and a smiley face shape similar to the arrow on the Amazon logo.

Bertha was disassembled and removed from the receiving pit by the end of August 2017. Two control room consoles and four cutting pieces went to the Museum of History and Industry for future display.

The tunnel project had millions in cost overruns, and lawsuits would determine the final cost. On December 13, 2019, a Thurston County jury awarded WSDOT $57.2 million and said Seattle Tunnel Partners was responsible for Bertha's breakdown and the SR 99 tunnel construction stalls.

"We never wavered from our position that it was always the contractor's responsibility to fix the tunneling machine and that taxpayers should not pay the repair bill," Inslee said in a statement. "We are grateful the jury agreed and awarded damages to taxpayers for a tunnel delivered three years behind schedule" ("Inslee, Millar statement ..."). Three days later, attorneys for Seattle Tunnel Partners said they would appeal the verdict, and the case was expected to last well into 2020.


Mike Lindblom and Michelle Baruchman, "As The Highway 99 Tunnel Opens, Here Are Answers To Your Questions About The Project," The Seattle Times, January 31, 2019 (; Mike Lindblom, "'Nothing More Than a Toothpick': Court Showdown Begins Over Bertha's Delay In Highway 99 Tunnel," Ibid., October 10, 2019; Mike Lindblom, "MOHAI Takes Bertha's Control-Room Consoles For A Future Display," Ibid., August 4, 2017; Mike Lindblom, "Bertha's Nemesis: 119-Foot Steel Pipe," Ibid. January 3, 2014; Natalie Guevara and Genna Martin, "Making History: Thousands Gather To Celebrate Opening Of New SR-99 Tunnel,", February 2, 2019 (; Scott Gutierrez, "McGinn Absent At SR99 Tunnel Groundbreaking," Ibid., June 6, 2012; Chris McGann, "Gregoire: 'Watch Me' Tear Down The Viaduct," Ibid., January 3, 2008; Gov. Inslee: Bertha's Breakthrough Is 'Historic,'" December 19, 2017, MyNorthwest website accessed December 19, 2019 (; Josh Kerns, "Bertha Starts Drilling New Seattle Tunnel Beneath Downtown," July 30, 2013, Ibid. accessed December 19, 2019 (; Josh Kerns, "Growing Crack Closes Pioneer Square Street Near Bertha," December 12, 2014, Ibid. accessed December 19, 2019 (; "Tunnel Timeline: From Conception To Tunnel Completion To Tolling," December 13, 2019, Ibid. accessed December 19, 2019 (; Sarah Anne Lloyd, "A Quick Guide To Seattle's Brand-New SR-99 Tunnel," February 19, 2019, Curbed Seattle website accessed December 19, 2019 (; "Seattle Tunnel Opening Celebration Set For February 2-3," October 31, 2018, website accessed December 19, 2019 (; "WSDOT: Contractor Knew About Steel Pipe In Bertha's Path," July 27, 2017, Ibid. website accessed December 19, 2019 (; Scott Sistek, "What A Snowy Month For The Seattle Record Books! A Look Back On The Snowstorms Of February," March 1, 2019, KOMO website accessed December 19, 2019 (; "Jury Awards WSDOT $57.2 Million In Seattle Tunnel Lawsuit," December 13, 2019, Ibid. accessed December 19, 2019 (; "February 2019: Seattle's Snowiest Month In 50 Years," February 11, 2019, Seattle Weather Blog accessed December 19, 2019 (; John Ryan, "New Map Shows Widespread Sinking Near Bertha Rescue Pit," December 11, 2014, KUOW website accessed December 19, 2019 (; John Wenz, "They're Finally Freeing Bertha, The Biggest Tunnel-Boring Machine In The World," April 1, 2015, Popular Mechanics website accessed December 19, 2019 (; "2-4-19 at 4 a.m.," February 4, 2019 (archived KIRO 7 morning newscast), KIRO 7 Video Collection, Special Collections, University of Washington Libraries, Seattle; "RAW VIDEO Final Commuter Vehicle Exits The Alaskan Way Viaduct, 1138 p.m. 1-11-19 (Silent DOT Camera)" January 11, 2019, Ibid., Special Collections, University of Washington Libraries; Jack Stewart, "After 4 Years, Seattle's Giant Tunneling Machine Finally Breaks Through," April 5, 2017, Wired website accessed December 19, 2019 (; Staff of HistoryLink, Seattle at 150: Stories of the City through 150 Objects from the Seattle Municipal Archives (Seattle: History Ink, 2019); @BerthaDigsSR99, tweet from 11:15 p.m., February 3, 2019, accessed December 19, 2019 (; Ibid., tweet from 12:17 a.m., February 4, 2019, accessed December 19, 2019 (; Ibid., tweet from 10:14 a.m., May 3, 2019, accessed December 19, 2019 (; @WSDOT, tweet from 7:42 a.m., February 2, 2019, accessed December 19, 2019 (; Ibid., tweet from 7 p.m., February 2, 2019, accessed December 19, 2019 (; @GovInslee, tweet from 4:20 p.m., February 15, 2019, accessed December 19, 2019 (; "Inslee, Millar statement on Thurston County Court verdict in favor of WSDOT," December 13, 2019, Washington Governor Jay Inslee's website accessed December 19, 2019 (; Laura Newborn, "It's The End Of The Road For The Alaskan Way Viaduct," January 11, 2019, Washington State Department of Transportation website accessed December 19, 2019 (; Steve Peer, "Gov. Inslee To Cut Ribbon For New SR 99 Tunnel This Weekend," February 1, 2019, Ibid. accessed December 19, 2019 (; Laura Newborn, "SR 99 Tunnel Set To Open Before Monday Morning Commute," February 3, 2019, Ibid. accessed December 19, 2019 (; Laura Newborn, "Crunch Time: Demolition Of The Alaskan Way Viaduct Begins," February 15, 2019, Ibid. accessed December 19, 2019 (; Laura Newborn, "Northbound Off-Ramp From SR 99 Opening For A New Way To Access Downtown Seattle," February 18, 2019, Ibid. accessed December 19, 2019 (; "SR 99 Tunnel Toll Rates," Ibid. accessed December 19, 2019 (; Laura Newborn, "How's Traffic In Seattle's SR 99 Tunnel?," April 5, 2019, WSDOT Blog accessed December 19, 2019 (; "SB 5768 – 2009-10," Washington State Legislature website accessed December 19, 2019 (; author's own recollections and observances.

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