Whenever it is necessary to secure any lands for primary or secondary state highway right-of-way or other state highway purposes, the title to which is in any county of the state or in any political or municipal subdivision of the state, which land is not at the time being used as a public highway, the county legislative authority or the board of directors or governing body of any such political or municipal subdivision are authorized to directly lease, sell, or convey by gift the land or any interest therein to the state of Washington, without requiring competitive bids or notice to the public, and at such price as the legislative authority, directors, or governing body may deem for the best interests of the county or for the best interests of the political or municipal subdivision of the state. The county legislative authority or the directors or governing body of any political or municipal subdivision are empowered to execute a deed or other proper instrument to the land, passing title to the state of Washington, and the instrument need not require consideration other than the benefit which may be derived by the grantor on account of the use thereof. Whenever any state highway is established by legislative enactment and the state highway is upon the former route of a county road, the county legislative authority shall cause the title to the existing right-of-way or so much thereof as the department requires to be transferred to the state of Washington by proper instrument.