When the Alaskan Way Viaduct closes Jan. 11, 2019, three solid weeks of construction begin. Crews will work around the clock to move State Route 99 off the viaduct and into the new, two-mile SR 99 tunnel beneath downtown Seattle. During the Realign99 closure, the longest highway closure in Seattle’s history, both the viaduct and new tunnel will be closed.
Why is so much work needed? Today the stretches of SR 99 immediately north and south of the tunnel are temporary road, detours built years ago to keep traffic moving during tunnel construction. On Jan. 11, crews will start removing the detours and completing the ramps to align SR 99 with the new tunnel. The work includes unburying tunnel on-and-off ramps completed in 2014 at the tunnel’s south end. This video explains more:
While the viaduct closes on Jan. 11, 2019, there will be earlier impacts to traffic. On Jan. 4, the southbound off-ramp at South Atlantic Street will close. Then after the tunnel opens, it will take up to two additional weeks to complete the new northbound off-ramp to Alaskan Way and South Dearborn Street. This is the ramp structure that today stands in the middle of the SR 99 detour just south of the viaduct.
The Realign99 closure will be a very challenging time for everyone traveling to, from or through Seattle. From past experience we know closing SR 99 makes other highways and Seattle streets more congested. We will need everyone’s help to avoid gridlock. Commuters, employers and travelers – start making your plan, consider changing your habits, follow the conversation on Twitter, and make sure you stay well informed once the closure begins.