Any county or city in this state is hereby authorized and empowered:
To acquire by purchase or by condemnation and to construct, or partly acquire and partly construct, and to improve, operate, and maintain bridges wholly or partially within the state within such county or city or within twenty miles of the territory over which such county or city has jurisdiction and which are over the Mississippi River; and
To issue bridge revenue bonds of such county or city, payable from bridge earnings, to pay the cost of such bridges.
No revenue bonds and no 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 this article constitute a lien on any other property of a city or county other than the bridge constructed or acquired under this article or a pledge of the credit of such agency unless specifically so voted by a majority of the qualified electors voting in favor of same in an election held according to law for the purpose of so authorizing.