Mo. Rev. Stat. § 226.500
The general assembly finds and declares that outdoor advertising is a legitimate commercial use of private property adjacent to the interstate and primary highway systems and that it is necessary to regulate and control same to promote highway safety, to promote convenience and enjoyment of highway travel, and to preserve the natural scenic beauty of highways and adjacent areas. The general assembly further declares it to be the policy of this state that the erection and maintenance of outdoor advertising in areas adjacent to the interstate and primary highway systems be regulated in accordance with sections 226.500 to 226.600 and rules and regulations promulgated by the state highways and transportation commission pursuant thereto and may confer with the department of public safety regarding highway safety, the department of economic development and the state division of tourism with regard to promoting the convenience and enjoyment of highway travel, and the departments of conservation and natural resources regarding the preservation of the natural scenic beauty of adjacent areas.
§ 226.500, RSMo