In late August, crews building the future north portal of the state Route 99 tunnel will close SR 99/Aurora Avenue North near South Lake Union for four days, Aug. 22 through 27. During this closure, crews will demolish and replace the section of SR 99 that crosses above Broad Street.

To minimize the need for additional closures, separate crews will complete the following work elsewhere along the SR 99 corridor during this time:

•Utility work at Harrison Street;

•Concrete panel replacement in SODO;

•Expansion joint repairs on the Alaskan Way Viaduct near the Seneca Street off-ramp; and

•Ivy removal from the viaduct.

From 10 p.m. Friday, Aug. 22 to 5 a.m. Monday, Aug. 25, SR 99 will close in both directions from the West Seattle Bridge to Valley Street.

Northbound SR 99 will open from South Royal Brougham Way until midnight on Friday, Aug. 22 for exiting Seahawks traffic.

From 5 a.m. Monday, Aug. 25 to 5 a.m. Wednesday, Aug. 27, SR 99 will close in both directions from the south end of the Battery Street tunnel to Valley Street. Travelers who use SR 99 should consider the following:

•Allow plenty of extra time, and expect additional congestion on alternate routes, including Interstate 5 and surface streets;

•Leave early or delay your trip to avoid traveling during peak commute periods in the morning and afternoon;

•Delay or reschedule discretionary trips;

•Consider telecommuting; or

•Choose an alternative travel mode, such as King County Metro, share a ride in a car or vanpool or walk or ride a bicycle.

Learn more about your commute and travel choices at