News

SR 99 closure planned late Friday, early Saturday for bridge demolition

If you plan to head into Seattle this weekend or use SR 99, there are some important traffic alerts to be aware of.

Round two of South Spokane Street timber bridge demolition will shut down State Route 99 approaching the West Seattle Bridge, starting at 10 p.m. Friday. Aug. 16. West Seattle travelers headed to and from downtown Seattle will be detoured to East Marginal Way South.

Both directions of SR 99 between South Nevada Street and the stadiums will be closed through Saturday morning, Aug. 17.

“We know West Seattle drivers and Hempfest fans are counting on Highway 99 this weekend,” said Washington State Department of Transportation project engineer Hien Trinh. “To help keep drivers moving, all northbound lanes and the ramps to the West Seattle Bridge will reopen by 8 a.m. Saturday.”

Closure details

Northbound SR 99

10 p.m. Friday to 8 a.m. Saturday

  • All lanes closed between South Nevada Street and South Royal Brougham Way.
  • Exit to East Marginal Way South and the Port of Seattle remains open.
  • West Seattle Bridge exit to northbound SR 99 will be closed.

Alternate routes

  • South of Diagonal Avenue South - Drivers will be directed onto First Avenue South to South Royal Brougham Way to northbound SR 99.
  • North of Diagonal Avenue South - All traffic must exit at East Marginal Way South. Take South Atlantic Street to Frontage Road to northbound SR 99.

Southbound SR 99

10 p.m. Friday to 8 a.m. Saturday

  • All lanes closed between South Atlantic Street and South Nevada Street.
  • The on-ramp to southbound SR 99 from East Marginal Way South remains open.
  • West Seattle drivers can access the low-level West Seattle Bridge from East Marginal Way South.

Alternate routes

  • All traffic must exit at South Atlantic Street – Drivers will be directed onto East Marginal Way South to northbound SR 99.

8 a.m. to noon Saturday

  • All lanes closed between just south of the West Seattle Bridge exit and South Nevada Street.
  • The on-ramp to southbound SR 99 from East Marginal Way South remains open.
  • West Seattle drivers can access the upper-level West Seattle Bridge from Highway 99.
  • All traffic must exit at South Atlantic Street or the West Seattle Bridge/Harbor Island exit.

When the highway opens Saturday morning, traffic will be on the east half of the bridge. The speed limit of 40 mph will remain in effect.

Friday’s overnight closure marks the halfway point of the South Spokane Street Overcrossing Project, which replaces a 57-year-old, timber-supported section of SR 99.

Crews are demolishing and rebuilding one half of the bridge at a time. Construction on the east half began in January and is now complete.

An estimated 45,000 travelers, including commuters and trucks carrying freight to and from the Port of Seattle, use this section of Highway 99 Monday through Friday. Traffic volumes are cut in half between 11 p.m. Friday nights to 8 a.m. Saturday mornings, which is why WSDOT chose that time for this week’s closure.

Tools for drivers

  • Subscribe to the Seattle Area News construction email update: go here and search for “Seattle Area News”
  • Seattle area traffic: www.wsdot.wa.gov/traffic/seattle
  • Traffic cameras: www.wsdot.wa.gov/traffic
  • Travel alerts: www.wsdot.wa.gov/traffic/trafficalerts
  • Traffic products for your mobile phone and other wireless devices:www.wsdot.wa.gov/traffic/seattle/products
  • Follow WSDOT on Twitter: @wsdot_traffic for Puget Sound traffic
  • Call 511 for traffic updates
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