(a) In addition to the powers granted under this chapter and without supervision or regulation by any state agency or local governmental entity, but subject to an agreement entered into under Subsection (c), the board of an authority may by resolution, and on making the findings set forth in this subsection, authorize the use of surplus revenue of a turnpike project or system for the study, design, construction, maintenance, repair, and operation of a highway or similar facility that is not a turnpike project if the highway or similar facility is:
(1) situated in a county in which the authority is authorized to design, construct, and operate a turnpike project;
(2) anticipated to either:
(A) enhance the operation or revenue of an existing, or the feasibility of a proposed, turnpike project by bringing traffic to that turnpike project or enhancing the flow of traffic either on that turnpike project or to or from that turnpike project to another facility; or
(B) ameliorate the impact of an existing or proposed turnpike project by enhancing the capability of another facility to handle traffic traveling, or anticipated to travel, to or from that turnpike project; and
(3) not anticipated to result in an overall reduction of revenue of any turnpike project or system.
(b) The board in the resolution may prescribe terms for the use of the surplus revenue, including the manner in which the highway or related facility shall be studied, designed, constructed, maintained, repaired, or operated.

(c) An authority shall enter into an agreement to implement this section with the department, the commission, a local governmental entity, or another political subdivision that owns a street, road, alley, or highway that is directly affected by the authority’s turnpike project or related facility.
(d) An authority may not:
(1) take an action under this section that violates, impairs, or is inconsistent with a bond resolution, trust agreement, or indenture governing the use of the revenue of a turnpike project or system; or
(2) commit in any fiscal year expenditures under this section exceeding 10 percent of its surplus revenue from the preceding fiscal year.
(e) In authorizing expenditures under this section, the board shall consider:
(1) balancing throughout the counties of the authority the application of funds generated by its turnpike projects and systems, taking into account where those amounts are already committed or programmed as a result of this section or otherwise; and
(2) connectivity to an existing or proposed turnpike project or system.
(f) Except as provided by this section, an authority has the same powers and may use the same procedures with respect to the study, financing, design, construction, maintenance, repair, and operation of a highway or similar facility under this section as are available to the authority with respect to a turnpike project or system.
(g) Notwithstanding other provisions of this section:
(1) any work on a highway in the state highway system must be approved by the department; and
(2) the department shall supervise and regulate any work on a highway in the state highway system.