Mo. Rev. Stat. § 49.267
Notwithstanding other provisions of law, the county commission of any county of the second class may set a speed limit on any county road, not within the limits of any incorporated city, town, or village, lower than that otherwise provided by law. However, in no case shall the speed limit be set lower than twenty-five miles per hour. The commission shall send copies of any such order to the superintendent of the state highway patrol. After the roads have been properly marked by signs indicating the speed limits set by the county commission, the speed limits so set shall be in full force and effect.
(L. 1977 H.B. 286 § 1, A.L. 1983 S.B. 219)
Effective 1-1-85