Wash. Rev. Code § 81.68.065
Any auto transportation company authorized to transport persons for compensation on the highways and engaging in interstate, or interstate and intrastate, operations within the state of Washington which is or becomes qualified as a self-insurer with the federal motor carrier safety administration of the United States department of transportation under the United States interstate commerce act applicable to self insurance by motor carriers, is exempt, so long as such qualification remains effective, from all provisions of law relating to the carrying or filing of insurance policies or bonds in connection with such operations.
The commission may require auto transportation companies to prove the existence and continuation of such qualification with the federal motor carrier safety administration by affidavit in any form the commission prescribes.
RCW 81.68.065