Mo. Rev. Stat. § 622.350

In all trials, actions, suits and proceedings arising under the provisions of this chapter or growing out of the exercise of the authority and powers granted in this chapter to the state highways and transportation commission, the burden of proof shall be upon state highways and transportation commission. The state highways and transportation commission shall show by clear and satisfactory evidence that the determination, requirement, direction or order of the state highways and transportation commission is reasonable or lawful as the case may be.