142.817.  Fuel tax exemption for certain public services. — Motor fuel sold to be used to operate public mass transportation service by a city transit authority, a city utilities board, or an interstate transportation authority, as such terms are defined in section 94.600, a city, or an agency receiving funding from either the Federal Transit Administration's urban or nonurban formula transit programs is exempt from the fuel tax imposed by this chapter.  The department shall promulgate rules to implement the provisions of this section.  Any rule or portion of a rule, as that term is defined in section 536.010, that is created under the authority delegated in this section shall become effective only if it complies with and is subject to all of the provisions of chapter 536 and, if applicable, section 536.028.  This section and chapter 536 are nonseverable and if any of the powers vested with the general assembly pursuant to chapter 536 to review, to delay the effective date, or to disapprove and annul a rule are subsequently held unconstitutional, then the grant of rulemaking authority and any rule proposed or adopted after August 28, 2007, shall be invalid and void.