Mo. Rev. Stat. § 227.221
Current with changes from the 2023 Legislative Session
The state transportation department shall mark all primary roads and highways outside the city limits of any incorporated city, town, or village with a white line along the outer or right-hand edge of such road or highway. The mark shall be made of the same substance and shall be of the same width as centerlines are on such roads and highways.
§ 227.221, RSMo