Tex. Transportation Code § 284.003

(a) A county, acting through the commissioners court of the county, or a local government corporation, without state approval, supervision, or regulation, may:

(1) construct, acquire, improve, operate, maintain, or pool a project located:

(A) exclusively in the county;

(B) in the county and outside the county; or

(C) in one or more counties adjacent to the county;

(2) issue tax bonds, revenue bonds, or combination tax and revenue bonds to pay the cost of the construction, acquisition, or improvement of a project;

(3) impose tolls or charges as otherwise authorized by this chapter;

(4) construct a bridge over a deepwater navigation channel, if the bridge does not hinder maritime transportation;

(5) construct, acquire, or operate a ferry across a deepwater navigation channel;

(6) in connection with a project, on adoption of an order exercise the powers of a regional mobility authority operating under Chapter 370; or

(7) enter into a comprehensive development agreement with a private entity to design, develop, finance, construct, maintain, repair, operate, extend, or expand a proposed or existing project in the county to the extent and in the manner applicable to the department under Chapter 223 or to a regional tollway authority under Chapter 366.

(b) The county or a local government corporation may exercise a power provided by Subsection (a)(6) only in a manner consistent with the other powers provided by this chapter. To the extent of a conflict between this chapter and Chapter 370, this chapter prevails.

(c) A project or any portion of a project that is owned by the county and licensed or leased to a private entity or operated by a private entity under this chapter to provide transportation services to the general public is public property used for a public purpose and exempt from taxation by this state or a political subdivision of this state.

(d) If the county constructs, acquires, improves, operates, maintains, or pools a project under this chapter, before December 31 of each even-numbered year the county shall submit to the department a plan for the project that includes the time schedule for the project and describes the use of project funds. The plan may provide for and permit the use of project funds and other money, including state or federal funds, available to the county for roads, streets, highways, and other related facilities in the county that are not part of a project under this chapter. A plan is not subject to approval, supervision, or regulation by the commission or the department, except that:

(1) any use of state or federal highway funds must be approved by the commission;

(2) any work on a highway in the state highway system must be approved by the department; and

(3) the department shall supervise and regulate work on a highway in the state highway system.

(e) Except as provided by federal law, an action of a county taken under this chapter is not subject to approval, supervision, or regulation by a metropolitan planning organization.

(f) The county may enter into a protocol or other agreement with the commission or the department to implement this section through the cooperation of the parties to the agreement.

(g) An action of a county taken under this chapter must comply with the requirements of applicable federal law. The foregoing compliance requirement shall apply to the role of metropolitan planning organizations under federal law, including the approval of projects for conformity to the state implementation plan relating to air quality, the use of toll revenue, and the use of the right-of-way of and access to federal-aid highways. Notwithstanding an action of a county taken under this chapter, the commission or department may take any action that is necessary in its reasonable judgment to comply with any federal requirement to enable the state to receive federal-aid highway funds.