Neb. Rev. Stat. § 14-1231: Neb. Rev. Stat. § 14-1231

No contract for acquisition, construction, or incidents thereto, and no liabilities in connection with such contract shall be entered into or incurred by a bridge commission of a city of the metropolitan class until bonds to finance the project have been authorized by the electors of the city in the method provided in section 14-1251 , or until revenue bonds, as authorized by section 14-1217 , have been issued by the city council.