3 week viaduct closure before new SR 99 tunnel opens to start in January

VIDEO: Seattle's traffic could get worse

SEATTLE — Major traffic jams expected to happen this fall will be delayed until next year.

This fall, the Washington State Department of Transportation was expected to shut down the Alaskan Way Viaduct for three weeks before the new SR 99 Tunnel opens to traffic.

Now, that closure will not happen until Jan. 11, 2019.

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The closure will run from the Battery Street Tunnel to South Spokane Street.  It's needed to realign SR 99 from the aging Alaskan Way Viaduct into the new the tunnel. The tunnel is expected to open a few weeks later, in the first week of February.

WSDOT says it will be the longest major highway closure the Puget Sound Region has ever seen, and commuters will face major traffic slowdowns from added traffic volumes on I-5, I-405 and I-90 as well as downtown Seattle surface streets. About 90,000 drivers who usually use the viaduct will need to find another route or mode of transportation to get to their destination.

“Before we can celebrate, we have to get through an unprecedented closure that will require all of us to change our behavior," said Brian Nielsen, administrator of the Alaskan Way Viaduct Replacement Program.

WSDOT says drivers should expect congestion for up to six weeks, before every new roadway is open.

Ramps at the tunnel’s south end will also close earlier and open later so crews can complete the large project of connecting SR 99 to the new tunnel.

WSDOT says the SR 99 southbound offramp to South Atlantic Street will permanently close about a week before the viaduct closure. The new SR 99 northbound offramp to Alaskan Way South and downtown Seattle will open up to two weeks after the tunnel opens.

Once the closure is over, the tunnel will open and SR 99 drivers will have a direct route from the stadiums to the Space Needle. The viaduct and Battery Street Tunnel will both closed permanently to prepare for the viaduct’s demolition in February.

WSDOT says the delay in the closure and opening of the new tunnel was caused by several factors:

  • Work by several contractors has to be completed before the three-week closure
  • Having the closure begin on January 11 will give the public more time to plan ahead
  • Avoiding a major highway closure between Thanksgiving and New Year's Day keeps people and good moving during the holiday season

"We were pushing for opportunities to be able to open as early as this fall, but those opportunities just didn't come to fruition," said Nielsen.

People who live in West Seattle and work downtown will be hit hardest by the traffic mess, which for them will also last longer, because a key downtown offramp from northbound SR99 won’t open for an additional couple of weeks.

To get people out of traffic, King County Metro will add a second water taxi so boats leave every 20 minutes.

More shuttles and parking are also planned near the dock in West Seattle.

The city plans to put police officers at key intersections to keep buses moving, and staff its traffic center around the clock to adjust the timing of lights.

WSDOT will open the HOV lane to all traffic on southbound I-5 through downtown, and SDOT will work with navigation apps to make sure drivers are routed to streets that are actually open.

King County Metro plans a dozen standby buses to help as needed.

During the closure, WSDOT recommends shifting travel times if possible, bike or walk, join a car or vanpool, use public transit, especially light rail or the King County Water Taxi or work from home if possible.

Monday's announcement also pushes back the schedule for demolishing the viaduct.

Contractors hoped to get that work done by next May, but now it is likely to extend into the summer season on the waterfront.

The tunnel is two miles long, has two lanes in each direction and an eight-foot safety shoulder.  There are no mid-tunnel entrances or exits, but there is a south portal just west of CenturyLink Field and a north portal just east of Seattle Center. The tunnel will be tolled, but the tolls will not start immediately after the tunnel opens. WSDOT could not provide a date for the start of tolls Monday.

Get more information about which ramps will be closed and the entire project at this link.