1. In order to secure funds for the purpose of acquiring, constructing, owning and operating, improving or extending, and maintaining toll bridges, and approaches thereto, all public agencies named in section 234.210 may issue negotiable toll bridge revenue bonds and sell such bonds to the United States government, or any authorized agency thereof, or other investor or investors.

2. In the event of the issuance and sale of bonds authorized by sections 234.210 to 234.300 by a public agency, such agency shall charge a reasonable toll for the use of any such toll bridge, the amount of which toll shall be sufficient to pay the reasonable cost of maintaining, repairing and operating such bridge and to provide a sinking fund sufficient to amortize and repay any such loan, including interest and financing cost, on such dates and within such period of time as may be agreed upon between the borrower and the original purchaser of such revenue bonds, and said tolls shall be used for no other purpose; and any public body which shall issue bonds under the provisions of sections 234.210 to 234.300 is hereby authorized and required to make all necessary provisions for the payment of principal and interest on any such bonds by the fixing, collecting, segregating, and allocating of the tolls and other revenues received from the operation of said bridge or bridges.

3. Such public agencies enumerated in section 234.210 may execute liens in proper form, pledging the revenue derived from the toll from such toll bridges or parts thereof which are constructed or acquired with funds borrowed as aforesaid, to the retirement of such bonds; provided, however, that no revenue bonds or any liens securing such bonds shall be repaid in whole or in part from any funds arising from taxation, nor shall any such bonds or liens, given under authority of sections 234.210 to 234.300 constitute a lien on any other property of any such public agency or a pledge of the credit of such agency; and provided further, that at such time when all moneys borrowed as aforesaid shall have been repaid, together with interest and charges thereon, no further toll shall be charged for the use of such bridges by the traveling public.

4. Such bonds may be made negotiable, may bear interest not to exceed six percent per annum, and may mature annually or semiannually, and may be sold at such time and in such manner as the issuing authority may determine upon.