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 Seventh Avenue North (formerly called 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's old path cut off east-west travel routes between South Lake Union and Seattle Center

Scope of work

Construction began 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 Seventh 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.

Effects of construction

The work will be conducted in phases that will keep at least one travel lane open in both directions on Seventh Avenue North. The first phase of work was on the inside lanes, where SR 99 previously entered the Battery Street Tunnel. That work was completed in June 2019, at which point the construction site shifted to the outside lanes and traffic moved to the newly built inside lanes.

During construction, neighbors and travelers should expect:

  • Barrels and concrete barriers to separate travel lanes from work areas.
  • Water misting to control dust.
  • Temporary detours for people walking, biking and driving.
  • Temporary and long-term bus stop relocations.
  • 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.

Seventh Avenue North final project configuration

When the project is complete, Seventh Avenue North (formerly called Aurora Avenue North) will have two lanes in each direction, plus transit lanes to help buses get to and from SR 99. In order to simplify the intersection of Seventh Avenue and Denny Way, the entrance to Seventh Avenue south of Denny Way was closed in June 2019. The former entrance to the street will be covered with a sidewalk built in the project’s later phases.

Schematic view of Seventh Avenue North showing lanes and landscaping

Click for larger PDF view.

Live construction photo camera: North surface streets project work

SR 99 northbound off-ramp bridge, southbound tunnel exit, northbound tunnel entrance (looking north)
View of Seventh Avenue North, looking south from Harrison Street. Video feed available on SDOT Travelers Home Page map.

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