Mo. Const. art. IV, § 31

Any state highway authorized herein to be located in any municipality may be constructed without limitations concerning the distance between houses or other buildings abutting such highway or concerning the width or type of construction. The commission may enter into contracts with cities, counties or other political subdivisions for and concerning the maintenance of, and regulation of traffic on any state highway within such cities, counties or subdivision. [Effective - 27 Feb 1945 , see footnote]