Neb. Rev. Stat. §§ 16-620
If the owners of the record title representing more than fifty percent of the front footage of the property abutting or adjoining any continuous or extended street, cul de sac, or alley of an improvement district created pursuant to section 16-617, or portion thereof which is closed at one end, and who were such owners at the time the ordinance creating such district was published, shall file with the city clerk, within twenty days from the first publication of such notice, written objections to the improvement of a district, such work shall not be done in such district under such ordinance, but such ordinance shall be repealed. If objections are not filed against any district in the time and manner provided in this section, the mayor and city council shall forthwith proceed to construct such improvement.
Neb. Rev. Stat. §§ 16-620