Mo. Rev. Stat. § 304.184
Notwithstanding any other provision of law to the contrary, any truck, tractor-trailer or other combination engaged in transporting solid waste, as defined by section 260.200, between any city and a solid waste disposal area or solid waste processing facility approved by the department of natural resources or department of health and senior services, may operate with a weight not to exceed twenty-two thousand four hundred pounds on one axle or a weight not to exceed forty-four thousand eight hundred pounds on any tandem axle; but nothing in this section shall be construed to permit the operation of any motor vehicle on the interstate highway system in excess of the weight limits imposed by federal statute; and no such truck, tractor-trailer or other combination shall exceed the width and length limitations provided in section 304.190.
§ 304.184, RSMo