The SR 99 tunnel’s southern entrance and exit will be between Alaskan Way South and First Avenue South, in Seattle’s SODO neighborhood. Much of this area was previously used to stage equipment and materials for the South Holgate to South King Street project.
The tunnel’s south portal will include:
- Ramps to and from both directions of SR 99. The off-ramp to a new Alaskan Way street will connect drivers to downtown Seattle.
- Improved system connectivity between SR 99 and I-90/I-5.
- Transit pathways and improved bike and pedestrian movements.
- Tunnel operations building along Railroad Way South.
The SR 99 tunnel’s northern entrance and exit will be near Harrison Street between Aurora Avenue North and Sixth Avenue North, in Seattle’s Uptown neighborhood.
The tunnel’s north portal will include:
- New SR 99 on- and off-ramps between Harrison and Mercer streets. The off-ramp to Aurora Avenue will connect drivers to downtown Seattle.
- A new Aurora Avenue surface street between Denny Way and Harrison Street with transit stops.
- New connections across Aurora Avenue at John, Thomas and Harrison streets.
- Tunnel operations building.
