Latest Program News

  • SR 99 tunnel systems testing continues

    Getting the tunnel ready for drivers is a big task. Contractor Seattle Tunnel Partners must install and test thousands of components and 90 interconnected systems that are needed to safely operate the SR 99 tunnel.

    Systems work began in March after crews completed the roadway inside the tunnel. STP is now conducting multi-layered tests of the tunnel's operational and safety systems. Pre-functional tests ensure that each piece of individual equipment works (a sprinkler head). Functional tests check that the equipment works together as a system (multiple sprinklers). Finally, integrated testing checks that multiple systems function together (heat detectors and video cameras that work with the fire suppression system).

    This video explains the complex safety systems inside the tunnel and how they work together to keep travelers safe.

    STP has completed many of these tests, including testing the sprinkler system, but has more critical work to go. STP recently submitted their latest construction schedule showing they could complete their work by late September. But because so much critical testing remains, WSDOT cannot verify this schedule.

    In the meantime, other contractors will move Alaskan Way out from under the viaduct and complete preliminary work to connect ramps and roads to the tunnel at both ends. Once the tunnel is complete and systems function as designed, we must close SR 99 through Seattle for about three weeks to realign SR 99 into the new tunnel.

    Our goal is to safely open the tunnel to traffic as soon as possible and begin removing the Alaskan Way Viaduct, but systems testing must advance before any dates for closing SR 99 or opening the tunnel can be determined.

    We recognize closing SR 99 will affect traffic around the region and we are working with the City of Seattle, Port of Seattle, King County and Sound Transit to help keep people and goods moving. We will provide about a month’s notice prior to closing SR 99 and will need everyone’s help to keep traffic moving. We’re encouraging people to start thinking about travel alternatives and make a plan for getting around when SR 99 is closed.

    Keep following our program website and program Twitter account for more information as we move closer to opening the tunnel and taking down the viaduct.

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    Order: 8.2

  • When a really big tunnel needs really small trucks

    When the SR 99 tunnel opens, a fleet of tiny trucks will help WSDOT crews maintain the tunnel – traveling in places most of us will never see. While you drive underneath Seattle, your car might be just a few feet above maintenance workers doing their jobs in these bright, yellow trucks.

    WSDOT received nine new maintenance vehicles over the summer. The vehicles will move into the new SR 99 tunnel after tunnel contractor Seattle Tunnel Partners completes all tunnel systems testing and turns the tunnel over to WSDOT. The four-wheelers will travel the two-mile road beneath the tunnel’s lower roadway; the smaller, three-wheel versions can drive in the narrow corridors on the tunnel’s west side (see graphic below).

    Tunnel cross section showing the corridors on the left and bottom

    All nine trucks are electric and will be housed in the tunnel’s north operations building where they can be recharged by simply plugging them into a standard outlet.

    Bigger maintenance jobs will require bigger equipment, like bucket trucks and flatbed lift trucks. All total, more than 30 pieces of equipment will make up the tunnel maintenance fleet dedicated to traffic and maintenance inside Seattle’s newest tunnel.

    The tunnel could open as soon as this fall, after an approximately three-week viaduct closure to realign SR 99 into the new tunnel.

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    Order: 8.4

  • This weekend’s southbound viaduct closure previews the big traffic challenge still to come

    First, a short closure and a small shift

    This weekend, contractor crews working for WSDOT will close southbound State Route 99 in order to pour a new concrete roadway near Seattle’s stadiums. Crews will close southbound SR 99 between the south end of the Battery Street Tunnel and the West Seattle Bridge from 9 p.m. Friday, June 22 through 6 a.m. Sunday, June 24.

    When the highway reopens, drivers will move to a new, short stretch of highway just south of the viaduct. Getting this roadway in place is important work that must occur before the SR 99 tunnel can open to drivers. 

    Below: the yellow outline is southbound SR 99 today. The green outline is southbound SR 99 after the traffic shift. The spur on the right side is the South Atlantic Street off-ramp, which will start earlier and lengthen slightly.

    Southbound SR 99 today through SoDo Seattle

    Southbound SR 99 after closure shifts traffic to new lanes

    Beyond the weekend work – a much bigger closure

    This weekend work is a small preview of what it will take to realign SR 99 into the new tunnel to get the tunnel ready to open.

    Ramps and a permanent SR 99 must be built over the current SR 99 roadway. This means WSDOT must close SR 99 through Seattle to complete the work that opens the tunnel to traffic. We estimate it will take three weeks of construction – which means three weeks with no Alaskan Way Viaduct and no tunnel. This blog post explains more.

    We don’t have a date yet for the three-week closure as a date depends on the timing of tunnel work. Currently the tunnel contractor is testing operational and safety systems to make sure the tunnel can operate safely. At this point in time, we estimate the tunnel could open later this fall. We will give drivers about a month’s notice before we close the viaduct forever and begin the three weeks of critical ramp and realignment construction.

    Three weeks of viaduct closure, plus additional time for ramp closures

    In addition to the three solid weeks of no viaduct/no tunnel, the southbound SR 99 off-ramp to South Atlantic Street will close one week early. This ramp provides access to I-5, I-90, SODO and the stadiums.  

    After the tunnel opens, the new northbound off-ramp into downtown could take up to two additional weeks to complete. Northbound drivers who don’t want to use the tunnel can continue to exit SR99 at South Spokane Street and take city streets into downtown. It will be a rough period for drivers as there could be up to six weeks of traffic impacts to Seattle.

    This map sequence shows how the viaduct closure and tunnel opening will play out.

    There’s time to plan

    When the closure starts (again, we will give about a month’s notice), we will need everyone’s help to keep traffic moving. From past closures, we know shutting down the viaduct has a  region-wide effect. So we are asking everyone to start thinking of potential alternatives now to help you later.

    Using available tools and having a game plan will be vital during the closure. We will have much more information about alternative ways (PDF) to keep people and goods moving as the closure approaches.

    It’s an exciting time here at WSDOT as we approach our end goal of replacing the aging and seismically unsafe Alaskan Way Viaduct with a much safer tunnel. Keep following our program website and program Twitter account for more information as we move closer to opening the tunnel and tearing down the viaduct.

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    Order: 8.5

  • Temporary Alaskan Way taking shape near tunnel’s south portal

    For decades, surface Alaskan Way stretched along the downtown waterfront, connecting travelers to the waterfront piers and providing north-south passage through downtown.

    Streetview of Alaskan Way from 2008 showing western position relative to viaduct

    Alaskan Way north of Seneca Street from 2008, via Google Streetview

    Since 2011, the street has been neatly squeezed in between the Alaskan Way Viaduct’s concrete footings. It was shifted to this alignment to clear space for SR 99 tunnel and other construction along the waterfront, but this location was always meant to be temporary. Eventually, the land Alaskan Way currently occupies would need to be cleared to allow for viaduct demolition.

    With demolition now on the horizon, we’ve begun restoring the street to its traditional location. Crews will continue this work over the summer and shift the street back to the west of the viaduct later this year, before the new SR 99 tunnel opens. The preparation for this shift is becoming visible as crews rebuild the roadway.

     

    The restored Alaskan Way will look much like it did the first time around. It will generally have two lanes in each direction, providing access to Colman Dock and waterfront businesses and buildings. Near the viaduct demolition work zone, the road may be narrowed to one lane in each direction, but access to Colman Dock and other properties will always be preserved.

    This configuration will remain in place until the Waterfront Seattle Project builds a new, permanent Alaskan Way in the footprint of the viaduct.

    South portal update

    A little farther south of this stretch of new pavement, an aerial view captures work building the roadways near the tunnel’s south portal. This view from the Columbia Tower shows the alignment of ramps and roadways coming into focus.

    Aerial view of the tunnel south portal

    The future ramps at the tunnel’s south portal cross what is today southbound SR 99 (click for bigger version)

    You can watch this road work from the construction camera we have mounted atop the tunnel’s south operations building. This south portal work is part of the SR 99 Connections Project, which is currently performing utility and roadwork on East Frontage Road South, between South Royal Brougham Way and South Atlantic Street.

    Crews hope to complete as much work as possible before the tunnel is ready to open. The final ramp connections, as you can tell from that map above, will go across the SR 99 mainline. So when the tunnel is ready, we will need to close SR 99 for approximately three weeks to realign the highway and connect it to the tunnel. We do not have a date for the closure yet, but we will be able to provide notice four to six weeks in advance.
     

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    Order: 9.0