This map shows the projects that will replace SR 99 through Seattle.
Click this map to see related projects.
Click on the project boxes for more information. Click the X in the corner to close this window
Building a new State Route 99 through Seattle
Major elements of the program include:
- A two-mile-long tunnel beneath downtown Seattle.
- A mile-long stretch of new highway that connects to the south entrance of the tunnel, near Seattle’s stadiums.
- A new overpass at the south end of downtown that allows traffic to bypass train blockages near Seattle’s busiest port terminal.
- Demolition of the viaduct’s downtown waterfront section.
- A new Alaskan Way surface street along the waterfront that connects SR 99 to downtown.
Our schedule page includes a list of all 30 projects that are led or funded by the state as part of this effort.
Half of the viaduct is already gone, demolished and replaced by crews at the south end of downtown, near Seattle’s stadiums. Completed on budget and one year ahead of schedule, this new section of SR 99 connects to the remaining viaduct along the waterfront to keep SR 99 traffic moving until the tunnel opens to traffic.
The SR 99 tunnel will change the way traffic uses SR 99 in Seattle. Drivers approaching the tunnel from either direction will face a choice depending on their destination: use the tunnel to bypass downtown or exit to city streets and head into downtown. At the tunnel’s north end, downtown access will be similar to today, with on- and off-ramps near Seattle Center. From the south, new on- and off-ramps will connect SR 99 to downtown via the new waterfront street.
We work closely with residents and businesses near the viaduct to help them through construction. Milepost 31, our award-winning project information center, helps attract visitors and business to Pioneer Square. WSDOT’s parking mitigation program focuses on strategies that offset construction-related on-street parking impacts in Pioneer Square and the waterfront neighborhoods.