(a) The governing body of a municipality may exempt from the requirements of Section 721.004:
(1) an automobile when used to perform an official duty by a:
(A) police department;
(B) magistrate as defined by Article 2A.151, Code of Criminal Procedure;
(C) medical examiner;
(D) municipal code enforcement officer designated to enforce environmental criminal laws; or
(E) municipal fire marshal or arson investigator; or
(2) an automobile used by a municipal employee only when conducting an investigation involving suspected fraud or other mismanagement within the municipality.
(b) The commissioners court of a county may exempt from the requirements of Section 721.004:
(1) an automobile when used to perform an official duty by a:
(A) police department;
(B) sheriff's office;
(C) constable's office;
(D) criminal district attorney's office;
(E) district attorney's office;
(F) county attorney's office;
(G) magistrate as defined by Article 2A.151, Code of Criminal Procedure;
(H) county fire marshal's office; or
(I) medical examiner; or
(2) a juvenile probation department vehicle used to transport children, when used to perform an official duty.
(c) An exemption provided under this section does not apply to a contract deputy.