(A) Except as provided in § 30.25 and division (B) below, an ordinance for the government of the village which has been adopted by the Board of Trustees without submission to the voters of the village shall not go into effect until 15 days after the passage of the ordinance.
(Neb. Rev. Stat. § 19-3701)
(B) In the case of riot, infectious or contagious diseases or other impending danger, failure of a public utility or any other emergency requiring its immediate operation, an ordinance shall take effect upon the proclamation of the Chairperson and the posting thereof in at least three of the most public places in the village. The emergency ordinance shall recite the emergency, be passed by a three-fourths’ vote of the Board of Trustees and be entered of record on the Village Clerk-Treasurer’s minutes.
(Neb. Rev. Stat. § 17-613)