Author Archives: viaduct

Special event Sept. 24 at Seattle Center: Our Future Waterfront

Big changes are coming to our waterfront – the world’s largest-diameter bored tunnel; a new seawall that protects our city and improves habitat; and 26 blocks of new parks, paths and public space. Join the SR 99 Tunnel Project, the Elliott Bay Seawall Project and Waterfront Seattle at a full-day event at Seattle Center to discover how these projects are working together to transform Seattle’s downtown waterfront.

Join us on Sept. 24 at the Seattle Center Armory/Center House

  • Noon to 6 p.m. – Explore interactive models of the SR 99 tunnel boring machine, the existing seawall and conceptual waterfront designs.
  • 6 p.m. to 7:30 p.m. – Geek out on project details during a presentation and discussion with agency directors and industry experts.

This event is part of Seattle Center’s The Next 50: Celebrating the 1962 World’s Fair and its Legacy. Click here for more details.

It’s okay to stare – WSDOT is preparing to make tunneling history

Usually, it’s not polite to stare, but in this case it’s history in the making, so it’s encouraged. Crews are preparing right now for the world’s largest-diameter tunnel-boring machine to arrive in 2013. The Washington State Department of Transportation is inviting the public to stare in amazement at the massive work zone for the State Route 99 tunnel project.

Join project leaders this week on a mile-long, round-trip walking tour along the bicycle/pedestrian path adjacent to the construction site. Watch crews dig the launch pit for the 300-foot-long tunnel-boring machine and hear explanations of the equipment being used to do the work.

Although the five-story-tall tunneling machine won’t take the stage until next year, its supporting cast – including a fleet of massive cranes, drill rigs and excavators at work to the west of CenturyLink Field – are impressive in their own right. In addition to digging the 80-foot-deep pit where the machine will begin its northward journey, crews are building a new overpass and putting the finishing touches on a new section of SR 99 to replace the south end of the Alaskan Way Viaduct.

The tour will begin at Milepost 31, the Alaskan Way Viaduct Replacement Program’s information center in Pioneer Square. This center houses interactive exhibits, a model of the SR 99 tunnel-boring machine and the latest project information.

Walking tour details(pdf 276 kb)

6 p.m., Thursday, Sept. 6

Meet at Milepost 31, 211 First Ave. S., Seattle

For those who can’t attend, a new self-guided tour is available. Displays have been installed along the bicycle/pedestrian path to describe construction activities, machinery at work and the area’s history. Access to the path’s north entrance is available at South King Street and Alaskan Way South, a few blocks south of Colman Dock, or the south entrance is at South Atlantic Street and Alaskan Way South, west of Safeco Field. Maps are available at Milepost 31. Construction cameras and Flickr photos also provide a regularly updated view of the work zone.

Learn more about the Alaskan Way Viaduct Replacement Program at and Milepost 31, which is open 11 a.m. to 5 p.m. Tuesdays through Saturdays and is open late during Pioneer Square’s First Thursday Art Walk. Admission to Milepost 31 is free.

Replica of SR 99 tunnel boring machine on display now at Milepost 31 in Seattle

The world’s largest-diameter tunnel boring machine will arrive in Seattle next year, but you don’t have to wait until then to check it out. A 10-foot-long, motorized replica of the machine is on display now at Milepost 31, an award-winning information center that highlights the people and projects that shaped Pioneer Square and provides an inside look at the SR 99 Tunnel Project.

About 35 times smaller than the real thing, the model offers an up-close look at the inner workings of the five-story machine that will dig the SR 99 tunnel. The push-button display allows visitors to control some of the model’s parts, demonstrating how the real machine will work as it bores up to 200 feet beneath downtown Seattle.

Check out the model and other cool exhibits at Milepost 31, located at 211 First Ave S., between 11 a.m. and 5 p.m. Tuesdays through Saturdays. Admission is free.

For more information about Milepost 31, visit

SR 99 tunnel construction brings big changes to Seattle’s downtown waterfront

It’s not yet time for the downtown waterfront’s big makeover, but it is make-room time for the State Route 99 Tunnel project. Crews clearing space for tunnel construction are preparing to reroute six blocks of waterfront traffic from Alaskan Way to a newly improved road beneath the Alaskan Way Viaduct.

The traffic switch – which will happen Wednesday evening, May 9 and last through at least early 2014 – will change ferry access as well as parking and traffic patterns along the waterfront south of Spring Street. A detailed map of the changes, along with a drive-through simulation that shows new routes to the ferry terminal, is available on the program website.

Moving traffic off Alaskan Way allows crews to expand the tunnel work zone north to Yesler Way. The space will be used to prepare the ground beneath Alaskan Way, where the project’s tunnel boring machine will begin its journey in 2013. 

The Washington State Department of Transportation and the Seattle Department of Transportation are rerouting existing roads along the waterfront and in Pioneer Square, and implementing strategies to keep traffic moving while maintaining access to businesses in those neighborhoods, including:

  • Allowing drivers to use Yesler Way to exit the ferry terminal
  • Increasing the width of Alaskan Way between Yesler Way and Spring Street to accommodate ferry holding lanes
  • Adding more than 60 temporary on-street parking spaces on Alaskan Way between Spring and Pike streets
  • For more information on the Alaskan Way Viaduct Replacement program, visit

    Mother’s Day Deal: State, City partner with businesses to offer free parking on Seattle’s Waterfront

    The Washington State Department of Transportation (WSDOT) and the city of Seattle are teaming up with several waterfront businesses, restaurants and parking operators to offer up to four hours of free parking between 9 a.m. and 7 p.m. on Mother’s Day, May 13.

     For more information about the Mother’s Day parking promotion, visit