(a) As used in this section, "county road" means a public road that is not a state highway, interstate highway, or city street within the jurisdiction of a given county.
(b) (1) Each county judge may establish speed limits on county roads within the jurisdictional boundaries of his or her county.
(2) If a county judge has not established a speed limit on a county road within the jurisdictional boundaries of his or her county, then the speed limit shall be forty miles per hour (40 m.p.h.) on the county road.
(c) (1) A person who pleads guilty or nolo contendere to or is found guilty of a violation of a speed limit on a county road established by a county judge or as provided under this section shall be assessed a penalty as provided under § 27-50-305.
(2) A person who pleads guilty or nolo contendere to or is found guilty of speeding in excess of fifteen miles per hour (15 m.p.h.) over the posted speed limit on a county road established by a county judge or as provided under this section is guilty of a Class C misdemeanor.
(d) A traffic-control device that is erected on a county road shall conform to the uniform manual on traffic-control devices adopted by the State Highway Commission.