The commanding officer of any portion of the organized militia or his representative performing any militia duty in any street or highway may require persons in such street or highway to yield the right-of-way to such militia, except that the carriage of the United States mail, the legitimate functions of the police and fire apparatus, shall not be interfered with thereby. Any person who hinders, delays or obstructs any portion of such militia performing any militia duty, or who attempts to do so, is guilty of a misdemeanor.
§ 41.740, RSMo