(a) Except as provided by Subsection (b), this subchapter applies only to a municipality:
(1) with a population of 50,000 or more; or
(2) that has adopted Chapter 143.
(b) This subchapter does not apply to a municipality that:
(1) has adopted Chapter 174;
(2) is covered by Subchapter H, I, or J, Chapter 143; or
(3) has a population of one million or more and has not adopted Chapter 143.