233.500.  Establishment authorized — boundaries of subdistrict. — 1.  Within the boundaries of any special road district established under the provisions of section 233.015, 233.170 or 233.320, or in an area within a county which is not included in any special road district, the county commission may create a special road subdistrict in the manner prescribed in sections 233.500 to 233.520.  Any such subdistrict established shall be a body corporate and possess the usual powers of a public corporation for public purposes, and shall be known as "______ Special Road Subdistrict of ______ County" and in that name shall be capable of suing and being sued, of holding such real estate and personal property as may at any time be either donated to or purchased by it in accordance with the provisions of sections 233.500 to 233.520, and of contracting and being contracted with as provided in sections 233.500 to 233.520.

  2.  Special road subdistricts so organized shall consist of a public road of one mile or more in length and the adjacent lands one-fourth of a mile or more on either side of such public road, including adjacent roads one-fourth of a mile or more from the public road, and any such special road subdistrict shall have an assessed valuation of at least one million dollars, according to the last available report of the state tax commission.