Latest Program News

  • DAILY UPDATE: Latest on Realign99 closure

    Read the daily construction and traffic updates for the #Realign99 closure.

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  • Jan. 15 #Realign99 update: South end commuters feeling the squeeze

    Update: 6:45 p.m.

    The Puget Sound region saw a pretty good evening commute tonight, aided by dry weather and quick work by crews clearing traffic incidents. WSDOT, SDOT and King County Metro are monitoring transit travel times and looking for places where traffic signal timing or other changes could be made to keep buses moving.

    West Seattle Water Taxi demand remains strong and Ride2 West Seattle shuttles are in service. There's also more frequent service on free shuttle routes 773 and 775. King County Metro deployed standby buses on 51 trips today and carried an estimated 1,700 riders on those buses.

    Keep up the good work and enjoy the good weather while we can. The forecast is looking less summer-in-January for the end of the week. 

    Posted at 12:03 PM

    Thanks to another dry morning, crews building connections to the new tunnel continue to make good progress. They expect to finish removing geofoam from the new South Royal Brougham Way northbound on-ramp later today. Following that, they’ll focus their efforts on installing highway barriers. Several concrete pours will occur in the coming days at both the north and south portals. Striping is also underway on new sections of roadway. Overall, work is proceeding as planned.

    The morning commute was slightly less favorable than the weather. After a smooth commute on Monday, Tuesday got off to a rough start. Several incidents slowed traffic during the morning commute, which again started earlier than usual. South end commuters had slower travels than most. Travel times on northbound I-405 and northbound SR 167 were approximately 10 minutes slower than usual.

    Still, many other corridors were flowing smoothly, and in some cases better than normal. Travel times on southbound I-5 between Everett and Seattle were faster than usual. Overall, travel times were close to normal on many routes. 

    With increased congestion on the West Seattle Bridge, many West Seattleites are taking advantage of increased Water Taxi service. Yesterday, West Seattle Water Taxi ridership was up 269 percent from the same day last year, with some capacity remaining on boats.

    If you still need help making a plan for your commute, our closure page has resources and ideas. Look here for daily updates on traffic and construction progress throughout the #Realign99 closure. Track construction on our time-lapse cameras, and be sure to follow us on Twitter for updates, photos and videos. 

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  • Road to tunnel’s south portal begins to take shape this weekend

    The new SR 99 tunnel’s south portal sits just west of Pioneer Square and the stadiums, on the southwest corner of downtown. One big piece of work to be accomplished during the #Realign99 closure is building a new street connecting the south portal’s on- and off-ramps to First Avenue South.

    That one-block street will be called South Dearborn Street, as labeled in the rendering below:

    Rendering of south tunnel portal with South Dearborn Street labeled

    Building South Dearborn Street requires removing part of the ramp structure (see it on Google Maps) that today carries northbound SR 99 from the construction detour up onto the viaduct. Crews will demolish the ramp this Saturday and Sunday, crunching the concrete in daytime hours while working on the future intersection’s traffic lights at night. The work will close Railroad Way South for the weekend; our Construction Notices and Detours page has more information.

    Yesterday Rhine Demolition, the subcontractor doing the demolition, moved equipment into the work site:

    Heavy machinery sitting adjacent the viaduct ramp, with stadium in background

    While this is technically demolition work, removing this section of ramp is not the start of true viaduct demolition. This short span of ramp is the only part of the structure that will be taken down before the new tunnel opens. The full-fledged viaduct demolition is scheduled to begin in early-mid February.

    With the ramp down, crews can pave the new South Dearborn Street beneath the (closed) southbound SR 99 ramp structure and build the new intersection with First Avenue South. Our new videos offer more detail on how South Dearborn Street works for northbound drivers getting off SR 99 right before the tunnel, or southbound drivers getting onto southbound SR 99 right after the tunnel.

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  • Rolling with it: How the SR 99 tunnel is designed to withstand earthquakes

    You’ve heard it before but it bears repeating: the primary purpose of the Alaskan Way Viaduct Replacement Program is safety. The viaduct is an aging and seismically vulnerable structure, and retiring it from our highway network will make us all safer.

    It’s not just addition by subtraction. We are replacing the viaduct with a modern tunnel, built with sophisticated systems that work together to keep vehicles moving and drivers safe. Learn more about how the tunnel’s systems work on our new Tunnel Safety page.

    The viaduct’s vulnerability to earthquakes was the biggest motivation for its replacement, and here is another way the new tunnel shines. As it happens, tunnels are a rather safe place to be in an earthquake. If you find this counterintuitive, we’ve produced a video in conjunction with seismic and structural experts to help us explain:

    Engineers in our earthquake-prone region designed the tunnel to withstand a strong earthquake – roughly one that happens every 2,500 years. This would include a magnitude 9 earthquake off the coast of Washington, where the Juan de Fuca plate of the earth’s crust forms the Cascadia Subduction Zone. The tunnel design also takes into account earthquakes that might occur along the Seattle Fault.

    There are many design elements that work together to create a safe tunnel:

    • Structure: The SR 99 tunnel is built with more than 1,400 strong concrete and steel rings, each 6.5 feet wide. These rings are bolted together to form the tunnel, and while very sturdy, they have some flexibility to account for ground movement. This means they can move and return to their round shape. The roads inside are also designed to be flexible, allowing them to move with earthquake waves and remain functional.
    • Shape: The round tunnel can withstand lots of pressure from the outside – much like a submarine underwater keeps its round shape and withstands oceanic pressure.
    • Location: Tunnels that are deep underground experience less movement from the energy waves of earthquakes. Those energy waves increase in size as they approach the surface, so a tunnel will not experience the same degree of movement as an above-ground structure like a viaduct.

    The inherent advantages of a tunnel, combined with state-of-the-art seismic engineering, means the new SR 99 tunnel is designed to stand up to future earthquakes.

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