(a) Whenever local authorities in their respective jurisdictions determine on the basis of an engineering and traffic investigation that the maximum speed permitted is greater or less than is reasonable and safe under the conditions found to exist upon a highway or part of a highway, the local authority may determine and declare a reasonable and safe maximum limit thereon which:

(1) Decreases the limit at intersections;

(2) increases the limit within an urban district but not to exceed the maximum speed of 65 miles per hour;

(3) decreases the limit outside an urban district, but not to less than 20 miles per hour, except as authorized by Kan. Stat. Ann. § 8-1560a, and amendments thereto;

(4) decreases the limit within an urban district in a school zone to not less than 20 miles per hour, except that any such decreased limit shall apply only during the hours in which students are normally en route to or from school, such zones and hours to be determined by ordinance or resolution of such local authority; or

(5) decreases the limit within any residence district, but not to less than 20 miles per hour.

(b) Except as provided in subsection (h), local authorities in their respective jurisdictions may determine by an engineering and traffic investigation the proper maximum speed for all arterial streets and shall declare a reasonable and safe maximum limit thereon which may be greater or less than the maximum speed permitted under this act for an urban district or other location in which the arterial street is situated, except that in no event shall any local authority establish any such maximum limit in excess of 65 miles per hour.

(c) Except as otherwise provided in paragraph (4) of subsection (a), any altered limit established as authorized shall be effective at all times or during hours of darkness or at other times as may be determined when appropriate signs giving notice thereof are erected upon such street or highway.

(d) Any alteration of maximum limits on city connecting links shall not be effective until such alteration has been approved by the secretary of transportation.

(e) If local authorities in their respective jurisdictions have established a speed limit within any residence district which is less than 30 miles per hour, prior to the effective date of this act, such speed limit shall be deemed valid and shall not require an engineering and traffic investigation.

(f) Local authorities in their respective jurisdictions may establish the speed limit within a road construction zone, as defined in Kan. Stat. Ann. § 8-1458a, and amendments thereto, upon any highway under the jurisdiction of such local authorities.

(g) The provisions of Kan. Stat. Ann. § 8-1560b, and amendments thereto, shall apply to the limitations on speed limits provided by subsection (a) of this section.

(h) Local authorities who have jurisdiction over county or township highways may determine based on an engineering and traffic investigation or without an engineering and traffic investigation the proper maximum speed for such county or township highways and shall declare a reasonable and safe maximum limit thereon which may be greater or less than the maximum speed permitted under this act, except that in no event shall any local authority establish any such maximum limit in excess of 65 miles per hour.