North surface streets

North surface street connections

Filling and sealing the Battery Street Tunnel provides an opportunity to rebuild and reconnect three streets in South Lake Union previously cut off by SR 99. Crews will rebuild Aurora Avenue North between Harrison Street and Denny Way, filling in the Battery Street Tunnel trench and reconnecting Harrison, Thomas and John streets east-west.

Aerial view of north end of tunnel with construction area highlighted in orange

SR 99 cuts off east-west travel routes between South Lake Union and Seattle Center

Scope of work

Construction begins Feb. 8, 2019 and is scheduled to be complete in mid-2020. The major elements of this work are:

  • Filling in the trench approaching the Battery Street Tunnel.
  • Rebuilding Aurora Avenue North between Denny Way and Harrison Street, including dedicated transit lanes.
  • Reconnecting Thomas and John streets, compatible with future green street improvements on Thomas Street.
  • Electrical duct bank, gas line and water line work.
  • Paving, sidewalks, striping and landscaping.

Construction impacts

The work will be conduced in phases that will keep at least one lane of traffic open in both directions on this stretch of Aurora Avenue North. The first area of work will be the inside lanes of Aurora Avenue North, where SR 99 previously entered the Battery Street Tunnel.

During construction, neighbors and travelers should expect:

  • Concrete barriers to separate travel lanes from work areas.
  • Water misting to control dust.
  • Temporary detours for people walking, biking and driving.
  • Temporary building and parking access restrictions according to previously negotiated Temporary Construction Easements.
  • Work primarily during daytime hours to minimize noise disruption to nearby residences and hotels.
  • Increased truck traffic while crews fill the north portal of the Battery Street Tunnel. This will require hundreds of truck trips to deposit embankment material.
  • Other typical construction effects such as increased dust, noise, vibration, and truck activity.

Aurora Avenue North conceptual channelization:

When the project is complete, Aurora Avenue North will have two lanes in each direction, plus transit lanes to help buses get to and from SR 99. 

Lane diagram showing Aurora Avenue North between Denny Way and Harrison Street

North surface streets project work

SR 99 northbound off-ramp bridge, southbound tunnel exit, northbound tunnel entrance (looking north)
View of Aurora Avenue North, looking south from Harrison Street

How to stay informed

Join the mailing list! Sign up to receive viaduct removal, Battery Street Tunnel decommissioning and north surface street updates by email by entering your email address on our subscription page.

Questions? Call the 24/7 program hotline at 1-888-AWV-LINE (298-5463) or send an email to