The northbound lanes of the Seattle tunnel will close for scheduled maintenance Friday night.

Washington State Department of Transportation (WSDOT) crews will close the northbound lanes from 10 p.m. Friday until 8 a.m. Saturday. The closure is to check systems inside the tunnel including fire detection systems, tunnel cameras, and overhead signs.

Also see | Tolling for Seattle tunnel delayed until fall

Northbound drivers will need to exit State Route 99 at Dearborn Street during the closure. 

Maintenance closures will occur each month, alternating between the north and southbound lanes. 

WSDOT fully closed the tunnel in June for maintenance and to assess the sprinkler system.

Join the Seattle Tunnel Traffic group on Facebook to ask questions and share concerns or ideas regarding the new SR 99 tunnel under downtown.