The tax amount distributed to the state in the manner provided by RCW
46.68.090, and all moneys accruing to the motor vehicle fund from any other source, less such sums as are properly appropriated and reappropriated for expenditure for costs of collection and administration thereof, shall be expended, subject to proper appropriation and reappropriation, solely for highway purposes of the state, including the purposes of RCW
47.30.030. For the purposes of this section, the term "highway purposes of the state" does not include those expenditures of the Washington state patrol heretofore appropriated or reappropriated from the motor vehicle fund. Nothing in this section or in RCW
46.68.090 may be construed so as to violate terms or conditions contained in highway construction bond issues authorized by statute as of July 1, 1999, or thereafter and whose payment is, by the statute, pledged to be paid from excise taxes on motor vehicle fuel and special fuels.