To finance any of the purposes or powers provided for in sections 14-1201 to 14-1252, the governing body of any such city shall in the first instance determine whether any purchase, condemnation or construction authorized by said sections shall be financed by bonds which are general obligations of the city and which may also be supported by a lien or mortgage on the bridge itself or upon the tolls to be derived therefrom, or both, or by revenue bonds as provided for in section 14-1217 and which are charged solely against the revenue to be derived from such bridge through the collection of tolls, or part one kind of bonds and part the other. It shall not have authority to purchase, condemn nor construct any bridge nor to issue any bonds, except the preliminary bonds specially authorized by section 14-1215, until first authorized by the majority vote of the electors voting on such proposition, which proposition shall indicate the method of acquiring the bridge and the kind or kinds of bonds, at a special election called for that purpose or at any general city or state election; Provided, no election and no vote of electors shall be required upon the question of acquiring or constructing any bridge or issuing revenue bonds as authorized by section 14-1217, for the acquisition or construction of any bridge located more than one mile from any existing bridge, other than a railroad bridge, if the governing body of such city shall determine by a vote of the majority of its members to dispense with such election or vote of electors as to such question. This grant of power to issue bonds is in addition to any other power which may now have been or hereafter may be conferred upon such city, and shall be free from the restrictions now imposed by the charter of the city upon the issuance of bonds and incurring of indebtedness, and subject only to the provisions of the Constitution of Nebraska. At such election the proposition shall be separate as to the bonds for each bridge to be acquired or constructed and the amount of bonds may be either a specific amount equal to the estimated total cost of every nature plus not to exceed twenty-five percent, or may be general and authorize the issuance of bonds in such amount as may be found necessary from time to time to complete the acquisition, construction, and equipment of the bridge and all costs incident thereto, or may be part one and part the other. For all purposes of financing, the total cost of any improvement authorized by sections 14-1201 to 14-1252 may include every item of expense in connection with the project, and among other items shall also include the cost of acquiring every interest of every nature and of every person in any existing bridge, the cost of constructing the superstructure, roadway, and substructure of any bridge, the approaches and avenues or rights-of-way of access thereto and necessary real estate in connection therewith, toll houses and equipment thereof and of the bridge, franchises, easements, rights or damages incident to or consequent upon the complete project expenses preliminary to construction, including investigation and expenses incident thereto, and prior to and during construction the proper traffic estimates, interest upon bonds and all such other expenses as after the beginning of operation would be properly chargeable as cost of operation, maintenance, and repairs.