Mo. Rev. Stat. § 300.250: Authority to restrict direction of movement on streets during certain periods.

1. The city traffic engineer is hereby authorized to determine and designate streets, parts of streets or specific lanes thereon upon which vehicular traffic shall proceed in one direction during one period and the opposite direction during another period of the day and shall place and maintain appropriate markings, signs, barriers or other devices to give notice thereof. The city traffic engineer may erect signs temporarily designating lanes to be used by traffic moving in a particular direction, regardless of the center line of the roadway.

2. It shall be unlawful for any person to operate any vehicle in violation of such markings, signs, barriers or other devices so placed in accordance with this section.