The tolls from a bridge or bridges for which a single issue of bonds is issued, except the part thereof required to pay the cost of maintaining and operating the bridge or bridges and to provide the reserves therefor provided for in the resolution authorizing the issuance of the bonds or in the mortgage or trust indenture, shall be set aside at such regular intervals as are provided in the resolution, mortgage, or trust indenture, in a sinking fund which is hereby pledged to and charged with the payment of:

(1)  The interest upon the bonds as that interest falls due;

(2)  The principal of the bonds as it falls due;

(3)  The necessary fiscal agency charges for paying principal and interest; and

(4)  Any premium upon bonds retired by call or purchase.  

The use and disposition of the sinking fund is subject to such regulations as are provided in the resolution authorizing the issuance of bonds, or in the mortgage or trust indenture, but, except as is otherwise provided in the resolution, mortgage, or trust indenture, the sinking fund is a fund for the benefit of all bonds without distinction or priority of one over another.  

Subject to the provisions of the resolution authorizing the issuance of bonds or of the mortgage or trust indenture, any moneys in the sinking fund in excess of an amount equal to one year’s interest on all bonds then outstanding may be applied to the purchase or redemption of bonds.  All bonds so purchased or redeemed shall immediately be cancelled and shall not be issued again.