Neb. Rev. Stat. § 39-1903

In case the levy mentioned in section 39-1902 is not sufficient to pay the entire amount of the indebtedness of the various road districts, the county board in such counties where a deficiency exists shall annually thereafter make other levies for this purpose not exceeding three and five-tenths cents on each one hundred dollars upon the taxable value of all the taxable property in such district in any one year until all the indebtedness against the road districts in such county has been paid.