Wash. Rev. Code § 47.04.015
Unless the language specifically indicates otherwise, or unless the context plainly requires a different interpretation:
Wherever in Title 47 RCW or in any provision in the Revised Code of Washington the term "Washington state highway commission", "the state highway commission", "the highway commission", "the commission" (when referring to the Washington state highway commission), "the department of highways", "Washington toll bridge authority", or "the authority" (when referring to the Washington toll bridge authority) is used, it shall mean the department of transportation created in RCW 47.01.031.
Wherever in Title 47 RCW or in any provision in the Revised Code of Washington the term "director of highways" is used, it shall mean the secretary of transportation, whose office is created in RCW 47.01.041.
RCW 47.04.015