(A) Except when a special hazard exists that requires lower speed for compliance with § 70.20, the limits set forth in this section and Neb. Rev. Stat. §§ 60-6,187, 60-6,188, 60-6,305 and 60-6,313 shall be the maximum lawful speeds unless reduced pursuant to division (B) below, and no person shall drive a vehicle on a highway at a speed in excess of such maximum limits:
(1) Twenty-five mph in any residential district;
(2) Twenty mph in any business district;
(3) Fifty mph upon any highway that is gravel or not dustless surfaced;
(4) Fifty-five mph upon any dustless-surfaced highway not a part of the state highway system;
(5) Sixty-five mph upon any four-lane divided highway not a part of the state highway system; and
(6) Sixty-five mph upon any part of the state highway system other than an expressway, a super-two highway or a freeway.
(B) The maximum speed limits established in division (A) above may be reduced by the Department of Transportation or the Board of Trustees pursuant to § 70.22 or Neb. Rev. Stat. § 60-6,188.
(C) The Board may erect and maintain suitable signs along highways under its jurisdiction in such number and at such locations as it deems necessary to give adequate notice of the speed limits established pursuant to division (A) or (B) above upon such highways.
(Neb. Rev. Stat. § 60-6,186) Penalty, see § 71.99