Bonds issued under the authority of RCW
47.10.812 through
47.10.817 must distinctly state that they are a general obligation of the state of Washington, must pledge the full faith and credit of the state to the payment of the principal thereof and the interest thereon, and must contain an unconditional promise to pay such principal and interest as the same becomes due. The principal and interest on the bonds must be first payable in the manner provided in RCW
47.10.812 through
47.10.817 from the proceeds of the state excise taxes on motor vehicle and special fuels imposed by chapter
82.38 RCW and vehicle-related fees. Proceeds of such excise taxes and vehicle-related fees are hereby pledged to the payment of any bonds and the interest thereon issued under the authority of RCW
47.10.812 through
47.10.817, and the legislature agrees to continue to impose these excise taxes on motor vehicle and special fuels and vehicle-related fees in amounts sufficient to pay, when due, the principal and interest on all bonds issued under the authority of RCW
47.10.812 through
47.10.817.