Traffic will return to the Seattle City Light access road on a one-way, piloted basis 9 p.m. Tuesdays through 4 a.m. Thursdays
OSO – Drivers traveling through the section of State Route 530 near the site of this spring’s tragic landslide should allow extra time for their trips on certain midweek dates during August.
Contractor crews from Guy F. Atkinson Construction have been making progress since June on building the new, elevated SR 530 just south of the existing roadway. To advance to the next phases of construction they will need to divert traffic from the existing roadway for 31-hour periods each week in August.
During those times, traffic will return on a one-way, piloted basis to a neighboring single-lane gravel road, known as the Seattle City Light access road. Pilot cars will escort westbound traffic at the top of the hour and eastbound traffic on the half hour, around the clock. Drivers are encouraged to arrive early.
“The detours for this project are scheduled during the middle of the week to minimize traffic impacts to the community, and avoid conflicts with major summer events,” said Washington State Department of Transportation Regional Administrator Lorena Eng. “We appreciate the continuing patience and support from the communities of Arlington, Oso and Darrington, as well as their many visitors this summer.”
The first set of detours to the Seattle City Light access road are currently scheduled for:
The detours are subject to cancellation based on construction progress. During these detours, crews will install two new culverts under the roadway for improved fish passage and complete paving, guardrail and restriping work to connect the new, elevated eastern section of the roadway with the existing SR 530.
At all other times during August, traffic will continue to operate on a two-way basis on the existing SR 530. Drivers should continue to add about 10 minutes to their trips, as they will experience intermittent flagging 6 a.m. to 6 p.m. Monday through Saturday to allow safe movement of construction vehicles and equipment.
WSDOT will announce any detour schedule changes in advance through a variety of means, including the project website, the SR 530 email list, project hotline, social media channels, traffic advisories and roadway signage.
Rules of the Seattle City Light access road
Next steps for the permanent road
Crews will continue working throughout the summer to build a permanent new section of SR 530 south of the existing roadway, moving next toward the west side of the slide area. Substantial completion of the new alignment is expected in early October.
The March 22 landslide changed the geography of the valley floor and the Stillaguamish River North Fork, increasing the chance of flooding along the corridor. As a result, the roadway must be rebuilt and elevated.
The SR 530 reconstruction project is funded with $28.1 million of Federal Emergency Relief funding.