Mo. Rev. Stat. § 191.777
More stringent ordinances or rules may be adopted by governing bodies or ...
191.777. More stringent ordinances or rules may be adopted by governing bodies or school boards. — Nothing in sections 191.775 and 191.776 shall prohibit local political subdivisions or local boards of education from enacting more stringent ordinances or rules.
(L. 1993 H.B. 348 § 3)