A municipality issuing revenue bonds for the payment of which it pledges the net revenues derived from the ownership and operation of parking meters shall, by the favorable vote at the election for the purpose of issuing the revenue bonds, be construed to have made a binding contract with the holders of the bonds that the municipality will not remove or discontinue the operation of the parking meters until the revenue bonds, and all interest thereon, for the payment of which the net revenues have been pledged, have been paid in full.