Mo. Rev. Stat. § 231.360
The county commission in all counties of the first class, as provided by law, shall have the power to provide for the building of sidewalks, curbs, gutters, combinations of curb and gutter, and roadways including grading therefor, along any street, avenue, road or highway in any unincorporated town, village or residence district in such county by and at the expense of the owner, or owners, of the lots fronting on said street, avenue, road or highway along the distance improved in proportion to the front feet. Whenever a petition therefor shall be filed with the county commission signed by a majority of the resident lot owners fronting on such street, avenue, road or highway, and liable to taxation therefor, which sidewalks, curbs, gutters or combinations of curb and gutter and roadways shall be constructed in such manner and of such dimensions as are herein provided.
§ 231.360, RSMo