43 Tex. Admin. Code § 25.40
Transportation Code, Subchapter F, Chapter 224, authorizes the Texas Department of Transportation (the department) to finance, design, construct, operate, or maintain one or more lanes on a state highway facility as high occupancy vehicle (HOV) or exclusive lanes and to charge a toll for these lanes. The department may also enter into agreements with various transportation entities for the design, construction, operation, and maintenance of HOV and toll lanes. In order to support the construction of infrastructure and traffic operation strategies designed to decrease traffic congestion, improve air quality, improve safety, and enhance the use of existing highways, this subchapter prescribes requirements for the designation, funding, and operation of HOV lanes, toll lanes, and exclusive lanes on the state highway system.
43 Tex. Admin. Code § 25.40