Bonds may be additionally secured by the pledging of, placing a charge upon, or otherwise making available any parking meter revenue. Until all bonds so secured have been paid, the legislative body of a city may allocate, pledge, place a charge upon, or otherwise make available its parking meter revenue or special taxes for periods of years for the financing or operation of any project authorized by this part and the payment of principal and interest on all or any type of bond issued and outstanding pursuant to this part.