SR 99 Connections

SR 99 Connections

One of the final pieces of work involved in opening the new SR 99 tunnel to drivers is connecting the tunnel to SR 99 at both ends. The SR 99 Connections Project encompasses this work. 

Street closures and night work

For the latest construction notifications, visit the Notices and detours page.

Timeline: February 2018 - end of 2018 (estimated)
Contractor: Scarsella Brothers, Inc.
24-hour noise hotline: 206-510-1428
Stay informed: Email to be added to the construction email list

Project overview

The contractor Scarsella Bros. will complete the ramp and road connections between the new tunnel and SR 99. Most of the work will take place in the existing construction areas for the SR 99 tunnel. There will also be some sign bridge work on SR 99 and surface street paving.

Map showing south portal construction area west of CenturyLink field
South end near stadiums
Map showing construction area at tunnel's north portal, just to east of Seattle Center
North end near Seattle Center

North portal work

Near the tunnel’s north end, crews will conduct final work to connect SR 99/Aurora Avenue North to the tunnel. Most of this work will happen during an approximately three-week closure of SR 99 right before the tunnel is ready to open to drivers. Crews will also pave a block of Sixth Avenue North that is currently part of the tunnel construction zone, and install traffic signals at the intersection of Aurora Avenue North and Harrison Street.

Work sequence at the tunnel's north portal (click for PDF)

Traffic routes at north portal when work is complete

South portal work

Scarsella Bros. crews will be busy in 2018 building the road connections between SR 99, surface streets, and the new tunnel. The graphics below show how most of the work will take place in what is currently the STP construction zone for the new tunnel. This includes creating a new stretch of South Dearborn Street.

However, when the tunnel is ready for drivers, the contractor will complete the ramps to the new tunnel, working in space that is today occupied by the SR 99 temporary bypass. This work is one reason why the viaduct will be closed for approximately three weeks right before the tunnel opens to traffic.

Work sequence at the tunnel's south portal (click for PDF)

Tunnel south portal showing final traffic routes