information from WSDOT

The Alaskan Way Viaduct will be closed from 6 a.m. to 6 p.m. Saturday, Oct. 8, and Sunday, Oct. 9, with both directions of State Route 99 closed between South Spokane Street and the north end of the Battery Street Tunnel for a semiannual inspection WSDOT closes the viaduct for inspection every fall and spring so WSDOT engineers can thoroughly examine the aging roadway and make sure it remains safe for drivers.

Also, between 6 a.m. and 3 p.m. Saturday, Oct. 8 only, crews working north of the Battery Street Tunnel will close SR 99 in both directions from the tunnel to Valley Street. Northbound drivers can access SR 99 at Valley Street.  
The Alaskan Way Viaduct is being replaced with a tunnel which is currently scheduled to open to traffic in January 2019.  
Details
• 6 a.m. to 6 p.m. Saturday, Oct. 8, and Sunday, Oct. 9: SR 99 will be closed between South Spokane Street and the north end of the Battery Street Tunnel.
• 6 a.m. to 3 p.m. Saturday, Oct. 8, the north end of the closure extends to Valley Street in both directions. Drivers wishing to travel north can access SR 99 by using the Valley Street entrance off Dexter Ave. North