43 Tex. Admin. Code § 27.40
Transportation Code, Chapter 366, authorizes two or more counties, if one of the counties has a population of not less than 300,000 and the counties form a contiguous territory, to create a regional tollway authority for the purpose of the expansion and improvement of transportation facilities and systems in this state. Unless one of the counties has a population of two million or more, the creation of a regional tollway authority requires that the counties gain the approval of the Texas Transportation Commission. Transportation Code, § 201.113 authorizes the Texas Transportation Commission and a regional tollway authority to enter into an agreement for the improvement by a regional tollway authority of portions of the state highway system. This subchapter prescribes the policies and procedures governing commission approval of the creation of a regional tollway authority and an improvement to the state highway system by a regional tollway authority.
43 Tex. Admin. Code § 27.40