Free Public Tours

Visit the SR 99 Tunnel Construction Viewing Platform

Join us for a free public tour to see SR 99 tunnel construction. In addition to learning about our efforts to replace the viaduct, visitors will be treated to views of this massive project from a section of the Alaskan Way Viaduct that has been permanently closed to traffic. Even after tunneling began in summer 2013 and Bertha slowly disappeared from view, the work site is full of activity as crews support tunneling operations.

Advance registration is required. You can sign up here or in person at the project information center, Milepost 31, located at 211 First Ave. S. in Seattle. If you have questions, please contact or 1-888-AWV-LINE (298-5463).

Tours are offered at the following times:

  • Tuesdays: 5:30 - 6:30 p.m.
  • Wednesdays: Noon to 1 p.m.
  • Thursdays: Noon to 1 p.m.
  • Fridays: Noon to 1 p.m. 
  • Saturdays: Noon to 1 p.m. and 3 to 4 p.m.


Please check this site frequently as we may be adding additional tour dates.

Tour details

  • The tours are ½ mile round trip. Visitors must be able to walk over uneven ground and climb up and down 50 stairs.*
  • Tours last one hour.
  • Tours begin at Milepost 31, 211 First Ave. S. in Pioneer Square in Seattle.
  • Parking is available on city streets and in nearby parking garages. Please visit for additional parking information.
  • Tours will be conducted rain or shine. Please dress for the weather. In cases of severe weather, such as snow or ice, tours will be cancelled with short notice.
  • No pets allowed.
  • Tours may be canceled for any reason. We will do our best to accommodate the public on a future tour but we cannot guarantee that there will be space available.


*Because the tour is within an active construction zone, we offer our guests with limited mobility an opportunity to participate in a self-guided tour  (pdf 466 kb) along the paved path west of the construction area. Accommodation requests for people with disabilities can be made by contacting the WSDOT Diversity/ADA Affairs team at or by calling toll-free, 855-362-4ADA (4232). Persons who are deaf or hard of hearing may make a request by calling the Washington State Relay at 711.


Important information

  • Tour participants must wear sturdy, closed-toe shoes. No sandals, flip-flops, high heels or slip-on shoes allowed.
  • No one under the age of 13 is permitted.
  • Minors age 13 through 17 must be accompanied by a parent or guardian.
  • Participants are advised not to wear skirts or dresses.
  • All participants must sign a liability waiver on the day of the tour.


We reserve the right to deny entrance to anyone not following these rules.


Stairway to the viewing platform on the lower level of the Alaskan Way Viaduct.

Stairway to the viewing platform on the lower level of the Alaskan Way Viaduct.



The launch pit where Bertha will begin her historic journey under downtown Seattle.

The launch pit where Bertha will begin her historic journey beneath downtown Seattle.