(a) An authority:
(1) is a public political entity and corporate body;
(2) has perpetual succession; and
(3) exercises public and essential governmental functions.
(b) The exercise of a power granted by this chapter, including a power relating to a station or terminal complex, is for a public purpose and is a matter of public necessity.
(c) An authority is a governmental unit under Chapter 101, Civil Practice and Remedies Code, and the operations of the authority are not proprietary functions for any purpose including the application of Chapter 101, Civil Practice and Remedies Code.