Three-week closure of SR 99

Three-week closure of SR 99

When the new SR 99 tunnel is ready to open, WSDOT will need to close the highway for approximately three weeks to realign SR 99 into the tunnel. Ramps at the tunnel’s south end will close earlier and open later to accommodate the large amount of work involved in connecting SR 99 to the new tunnel.

Closure details

What: Three-week closure of SR 99, from the Battery Street Tunnel to South Spokane Street

When: As soon as this fall (depends on contractors’ progress). WSDOT will provide notice approximately one month before the start of the closure.

Why: To build ramps and roadways connecting SR 99 to the new tunnel at both ends.

Ramps near stadiums closed for five to six weeks
The large amount of work required at the tunnel’s south end near the stadiums means that ramps will close sooner and open later than the rest of the highway. The SR 99 southbound off-ramp to South Atlantic Street will close approximately one week before the main closure begins. The new SR 99 northbound off-ramp to Alaskan Way S. and downtown will open up to two weeks after the tunnel opens to drivers.

After the closure ends
When the closure ends, the tunnel will open and SR 99 drivers will have a direct route from the stadiums to the Space Needle. The viaduct and Battery Street Tunnel will both be permanently closed in preparation for the start of the demolition project.


It's not too early to start making your plan! Here are resources to help:

  • Why is a closure necessary?: This WSDOT blog post explains the work that has to happen to open the tunnel to drivers.
  • Tell me my options: Looking for ideas to avoid bad traffic? Read this PDF for ideas and resources for changing your commute or travel habits.

Closure sequence

Labels for ramps show in maps above. SB = southbound; NB = northbound. Larger maps available as PDF here.

SR 99 ramps before and during highway closure (slides 1-3)
A SB off-ramp to South Atlantic Street
B NB on-ramp from South Royal Brougham Way
C Columbia Street SB on-ramp
D Seneca Street NB off-ramp
E Western Avenue NB off-ramp
F Elliott Avenue SB on-ramp
G Western Avenue NB on-ramp (into Battery Street Tunnel)
H Western Avenue SB off-ramp (from Battery Street Tunnel)
SR 99 ramps after tunnel opens (slides 4-5)
1 SB off-ramp to Stadiums, Interstates and Ferries (after leaving tunnel)
2 NB on-ramp from South Royal Brougham Way (into tunnel)
3 NB off-ramp to Alaskan Way S./Downtown (before tunnel)
4 SB on-ramp from South Dearborn Street
5 NB off-ramp to Mercer Street/I-5 (after leaving tunnel)
6 SB on-ramp from Sixth Avenue North (into tunnel)
7 SB off-ramp to Denny Way/Downtown (before tunnel)
8 NB on-ramp from Harrison Street