(a) Except as provided by Subsection (b), this subchapter applies only to:
(1) a municipality, and a police officer in a municipality, with a population of 50,000 or more;
(2) a municipality, and a police officer in a municipality, that has adopted Chapter 143; or
(3) a police officer not covered by a collective bargaining agreement adopted under Chapter 174 in a municipality that has adopted Chapter 174 for police officers in the police department, and the municipality that appoints or employs such a police officer.
(b) This subchapter does not apply to:
(1) a police officer who is covered by a collective bargaining agreement adopted under Chapter 174;
(2) a police officer who is covered by an agreement adopted under Subchapter H, I, or J, Chapter 143;
(3) a municipality that has a population of one million or more and has not adopted Chapter 143; or
(4) a municipality that has adopted Subchapter I, Chapter 143, in an election authorized by § 143.3015.