Tex. Transportation Code § 370.004

(a) The cost of acquisition, construction, improvement, extension, or expansion of a transportation project under this chapter includes the cost of:

(1) the actual acquisition, construction, improvement, extension, or expansion of the transportation project;

(2) the acquisition of real property, rights-of-way, property rights, easements, and other interests in real property;

(3) machinery and equipment;

(4) interest payable before, during, and for not more than three years after acquisition, construction, improvement, extension, or expansion as provided in the bond proceedings;

(5) traffic estimates, revenue estimates, engineering and legal services, plans, specifications, surveys, appraisals, construction cost estimates, and other expenses necessary or incidental to determining the feasibility of the acquisition, construction, improvement, extension, or expansion;

(6) necessary or incidental administrative, legal, and other expenses;

(7) compliance with laws, regulations, and administrative rulings, including any costs associated with necessary environmental mitigation measures;

(8) financing;

(9) the assumption of debts, obligations, and liabilities of an entity relating to a transportation project transferred to an authority by that entity;

(10) expenses related to the initial operation of the transportation project; and

(11) payment obligations of an authority under a contract or agreement authorized by this chapter in connection with the acquisition, construction, improvement, extension, expansion, or financing of the transportation project.

(b) Costs attributable to a transportation project and incurred before the issuance of bonds to finance the transportation project may be reimbursed from the proceeds of sale of the bonds.