This announcement from WSDOT:
Starting Wednesday, March 30 through Friday, April 8, crews will route bicycles off of both directions of Alaskan Way S. between S. Atlantic Street and S. Royal Brougham Way while they rebuild the entrance into the Port of Seattle’s Terminal 46. Cyclists will need to follow a signed detour route. For more information and a map, please see WSDOT’s project Web site.