Wash. Rev. Code § 47.12.080
The secretary of transportation may transfer and convey to the United States, its agencies or instrumentalities, to any other state agency, to any county or city or port district of this state, or to any public utility company, any unused state-owned real property under the jurisdiction of the department of transportation when, in the judgment of the secretary of transportation and the attorney general, the transfer and conveyance is consistent with public interest. Whenever the secretary makes an agreement for any such transfer or conveyance, and the attorney general concurs therein, the secretary shall execute and deliver unto the grantee a deed of conveyance, easement, or other instrument, duly acknowledged, as shall be necessary to fulfill the terms of the aforesaid agreement. All moneys paid to the state of Washington under any of the provisions hereof shall be deposited in the motor vehicle fund.
RCW 47.12.080