FAQs

FAQs  

Have additional questions?

Email viaduct@wsdot.wa.gov or call 1-888-AWV-LINE (298-5463)

General program questions

  • + Why is replacing the viaduct important to public safety?

    The Alaskan Way Viaduct was built in the 1950s, and decades of daily wear and tear have taken their toll on the concrete structure. While it remains safe for everyday use, it also remains vulnerable to earthquakes.
     
    The 2001 Nisqually quake damaged the structure and hastened plans for its replacement. WSDOT has since repaired and strengthened the viaduct, and conducts twice-yearly inspections for safety. Parts of the viaduct, however, remain built atop fill soil that could liquefy in an earthquake. A tunnel will provide a much safer roadway for people travelling along SR 99. 
     
    Replacing the aging seawall is another element of improving the Seattle waterfront's resiliency against earthquakes. Visit the Waterfront Seattle website for information on the seawall replacement project.

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  • + Is viaduct replacement construction being coordinated with other nearby projects?

    WSDOT coordinates with partner agencies on nearly every aspect of the program including overall strategy and management, project schedules, construction and public involvement. Project coordination extends beyond the SR 99 viaduct replacement - coordination with the Seawall Project, the Seattle Multimodal Terminal at Colman Dock ProjectWaterfront Seattle and many other projects is vital to keeping traffic and construction moving.

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  • + What will happen to the Battery Street Tunnel?

    The Battery Street Tunnel was constructed in the 1950s and is at the end of its useful life. WSDOT’s final environmental document for the program included decommissioning (filling and sealing) the tunnel, and so WSDOT has a legal obligation to implement that plan.
     
    Community ideas have been proposed for alternative uses for the tunnel. However, given the age and condition of the structure, it would need significant and costly structural and system upgrades in order to be safe for other uses. WSDOT will be decommissioning the tunnel as part of a design-build contract that also includes demolishing the viaduct and connecting surface streets at the tunnel’s north portal.

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SR 99 tunnel questions

  • + When will the SR 99 tunnel open to drivers?

    Seattle Tunnel Partners, as WSDOT's design-build contractor for the tunnel project, is responsible for the project schedule. Based on STP's most recent schedule, the tunnel could open to drivers as soon as fall 2018. WSDOT's goal is to safely open the tunnel to traffic as quickly as possible, but it’s too early to accurately predict a tunnel opening date. A significant amount of work remains before tunnel opening. Safety and quality remain our top priorities, and will continue to guide all work on the program.

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  • + Where is the tunnel located?

    The tunnel route begins on Alaskan Way South, south of South King Street, then moves toward First Avenue near Yesler Way, turns north near Stewart Street, and ends at Sixth Avenue North and Thomas Street.

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  • + How will northwest Seattle residents get to SR 99?

    Residents from northwest Seattle will have two options to get to or through downtown Seattle. They could travel along Elliott Avenue, as they do today, and drive down a new bridge over the railroad tracks near Pike Place Market to a new Alaskan Way street along the waterfront. Alaskan Way will connect directly to SR 99 near South Royal Brougham Way.

    If northwest Seattle residents want to use the SR 99 tunnel, they could take the new two-way Mercer Street to Sixth Avenue North and enter the tunnel at Republican Street. They could also use any of the existing connections to Aurora Avenue north of Mercer Street. Our Future Access Page shows example routes.

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  • + How many lanes will the tunnel have?

    Each direction of the tunnel will have two 11-foot travel lanes with an eight-foot safety shoulder and a two-foot shoulder. These lanes will ensure enough space for all vehicles and legal size trucks.

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  • + Will the tunnel have mid-town exits?

    The SR 99 tunnel will not have mid-town exits. The tunnel and a new Alaskan Way street are designed to work together to replace the functionality of the viaduct. The tunnel will have the capacity to accommodate trips through downtown, while the rest of today’s viaduct users will access downtown using ramps at either end of the tunnel. Along the waterfront, a new Alaskan Way street will provide several east-west connections to downtown, replacing the function of today’s midtown viaduct on-ramp and off-ramp.

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  • + Will the SR 99 tunnel be tolled?

    In 2013, WSDOT was directed by the Washington State Legislature to raise $200 million from tolls for the SR 99 Tunnel Project. The Advisory Committee on Tolling and Traffic Management studied ways to refine tolling of the SR 99 tunnel to minimize traffic diversion and meet funding goals, and investigate strategies to reduce or mitigate diversion. The committee submitted recommendations in 2014 (pdf 1.8 Mb).

    In summer 2016, WSDOT commissioned an independent traffic analysis firm to conduct a traffic and revenue study that will inform the toll rate setting process. Learn more about the study at WSDOT's Tolling page

    Toll rates for the SR 99 tunnel have not been determined. The Washington State Transportation Commission will oversee the rate-setting process closer to when the tunnel opens to traffic.

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  • + Will tolling cause diversion?

    The Advisory Committee on Tolling and Traffic Management reviewed several potential toll scenarios in an effort to meet the Legislature's $200 million toll-funding requirement and minimize traffic diversion. Results from their analysis are available online.  

    In summer 2016, WSDOT commissioned an independent traffic analysis firm to conduct a traffic and revenue study that will inform the toll rate setting process. Learn more about the study at WSDOT's Tolling page

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  • + Who will pay for the cost associated with the tunneling machine stoppage?

    In December 2013, Seattle Tunnel Partners (STP) stopped tunneling approximately 1,000 feet into the tunnel drive after measuring increased temperatures in the tunneling machine. While investigating the cause of the high temperatures, STP discovered damage to the machine’s seal system and contamination within the main bearing. STP and manufacturer Hitachi Zosen completed repairs to the machine in December 2015.

    In 2014, Seattle Tunnel Partners requested $125 million in additional compensation related to this stoppage. WSDOT denied that request after determining it had no contractual merit. The process for resolving disputes within the tunnel contract is prescriptive. It requires multiple steps by both parties. Should Seattle Tunnel Partners continue to pursue entitlement related to the stoppage, it will take time to resolve. Ultimately, the responsibility for costs associated with the delay will be determined through the project's design-build contract. 

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  • + Was any part of the tunneling machine saved for posterity or public viewing?

    The tunneling machine was owned by the original manufacturer, Hitachi Zosen, and the decision on what to do with the machine was theirs to make. Hitachi Zosen worked with The Port of Seattle and the Museum of History and Industry to preserve several pieces of the machine. The Port of Seattle received pieces of the cutterhead, and MOHAI received cutting tools and the machine's control panel. Most of the machine was recycled or preserved for use in other machines.

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Viaduct and demolition questions

  • + When will the viaduct be demolished?

    In 2011, crews demolished the southern mile of the viaduct, which accounted for nearly half the structure. The remaining portion of the viaduct will be demolished after the SR 99 tunnel opens to traffic. This work is currently expected to take up to nine months.

    A new Alaskan Way street will be built in place of the demolished viaduct. This road will connect over the railroad tracks to Elliott and Western avenues on the north end, and to SR 99 near the stadiums at the south end, while providing east-west connections to downtown. The City of Seattle's Office of the Waterfront is leading this project.

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  • + Is most of the traffic using the viaduct going to downtown or through downtown?

    Before we demolished the southern mile of the viaduct in October 2011, it carried approximately 110,000 vehicles per day just south of the mid-town ramps. Of this amount, approximately 17,000 vehicles entered or exited downtown at Columbia and Seneca streets, and 33,000 exited or entered at Elliott and Western avenues toward Belltown, Uptown, and neighborhoods along the 15th Avenue and Elliott Avenue corridor. The remaining 60,000 vehicles continued north through the Battery Street Tunnel, either exiting in the South Lake Union/Queen Anne area or continuing further north.

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  • + Is the viaduct still a safe structure on which to drive?

    Routine safety inspections and maintenance keep the viaduct safe for public use. In 2008, crews strengthened four column footings where the viaduct had settled approximately five-and-a-half inches into the ground since the 2001 Nisqually earthquake. The column safety project limits settlement in this area of the viaduct and prevents further damage to the structure.

    We also installed a system designed to close the viaduct automatically in the event of a moderate to severe earthquake in the greater Seattle area. The automated closure system consists of traffic gates at all viaduct access points controlled by an earthquake detection system. If the earthquake monitoring system detects significant ground movement, it will simultaneously lower all nine traffic gates and safely close the viaduct in two minutes.

    In 2011, crews demolished nearly half of the vulnerable viaduct near Seattle’s port and stadiums. Drivers now use a construction bypass connected to new side-by-side bridges built to current safety standards.

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Alaskan Way Viaduct looking north from SODO district.

Alaskan Way Viaduct looking north from SODO district. The southern mile of the viaduct was demolished in 2011.

 

Alaskan Way Viaduct looking south from Victor Steinbrueck Park, Pike Place Market.

Alaskan Way Viaduct looking south from Victor Steinbrueck Park, Pike Place Market.