(a) The commission shall cooperate with the Texas Department of Transportation to designate, interpret, and market State Highway 20 as a Texas historic highway.
(b) To supplement revenue available for the purposes under Subsection (a), the commission and the Texas Department of Transportation may pursue federal funds dedicated to highway enhancement.

(c) A designation of State Highway 20 as a Texas historic highway may not be construed as a designation under the National Historic Preservation Act (16 U.S.C. § 470 et seq.).
(d) The Texas Department of Transportation is not required to design, construct, or erect a marker under this section unless a grant or donation of funds is made to the department to cover the cost of the design, construction, and erection of the marker. Money received to cover the cost of the marker shall be deposited to the credit of the state highway fund.