A significant amount of construction continues at the SR 99 tunnel’s future north portal. The 80-foot-deep pit is where Bertha, the SR 99 tunneling machine, will emerge at the end of her two-mile journey beneath downtown Seattle.
Crews are also building the connection between the tunnel and Aurora Avenue North, and new on- and off-ramps at Republican Street. Our interactive simulation shows you how this area will change during construction.
When construction is complete, drivers, pedestrians and bicyclists will be able to travel between South Lake Union and Seattle Center via three improved east-west streets across the new Aurora Avenue North.
Current construction near Dexter Avenue North
To make room for SR 99 tunnel construction, crews are relocating utilities along Dexter Avenue North, and Harrison and Republican streets.
During this work, which began in spring 2014 and continues through the fall, Dexter Avenue North will be reduced to one lane in each direction between Thomas and Mercer streets. A separate bicycle lane will be maintained on Dexter Avenue North during peak commute times. Depending on the work activity, signs may direct bicyclists to merge with traffic during off-peak hours.
Harrison Street will be closed between SR 99/Aurora Avenue North and Eighth Avenue North. Later this summer, crews will reopen Harrison Street and then close Republican Street.
Other construction in the area
As you've likely noticed, the north end is bustling with construction activity. In addition to tunnel construction, our partners at the City of Seattle are making great progress on the Mercer Corridor Project. We’re coordinating closely with their construction, and will continue to do so as we move forward.