Thanks to the texter who alerted us to signage along 4th SW just south of Roxbury [map] about an impending road closure. We went over to check it out and spotted the signs you see above and below.

Following up with King County, since it’s their project, they confirmed the closure of a quarter-mile of 4th SW south of Roxbury is scheduled to start next Monday (April 1st) and provided this flyer (PDF) with details:

Background on Greenbridge is here.