The Washington State Department of Transportation has published details on the upcoming closure of the Alaskan Way Viaduct and subsequent opening of the SR 99 tunnel.

First ramps close Jan. 4. Realign99 closure sequence below:

10 p.m. Friday, Jan. 4: Stadium ramps close

• Northbound SR 99 on-ramp at South Royal Brougham Way closes (near stadiums; connection to I-90 and I-5).
• Southbound SR 99 off-ramp at South Atlantic Street closes (near stadiums; connection to I-90 and I-5).

10 p.m. Friday, Jan. 11: Full SR 99 closure through downtown Seattle begins

• SR 99 closes both directions from South Spokane Street to the south end of the Battery Street Tunnel.
• Battery Street Tunnel remains open with one lane in each direction. Ramps to and from Western Avenue remain open.
• West Seattle Bridge and off-ramps to First Avenue and Fourth Avenue remain open and do not close as part of Realign99.

10 p.m. Friday, Feb. 1: Battery Street Tunnel closes

• Battery Street Tunnel closes. All southbound SR 99 traffic must exit at Valley Street. Northbound SR 99 traffic can join highway at Valley Street.

Early February (exact date TBD): New tunnel opens

• SR 99 reopens about three weeks after Jan. 11, with highway using new SR 99 tunnel. Alaskan Way Viaduct and Battery Street Tunnel remain closed. One SR 99 off-ramp remains closed (see below).

Approx. 2 weeks later: Final ramp opens

• New SR 99 northbound off-ramp to downtown and Alaskan Way (just south of tunnel) opens, about two weeks after SR 99 tunnel opens.