(a) An authority is a body politic and corporate and a political subdivision of this state.
(b) An authority is a governmental unit as that term is defined in Section 101.001, Civil Practice and Remedies Code.
(c) The exercise by an authority of the powers conferred by this chapter in the acquisition, design, financing, construction, operation, and maintenance of a transportation project or system is:
(1) in all respects for the benefit of the people of the counties in which an authority operates and of the people of this state, for the increase of their commerce and prosperity, and for the improvement of their health, living conditions, and public safety; and
(2) an essential governmental function of the state.
(d) The operations of an authority are governmental, not proprietary, functions.