The definitions in this section apply throughout this subchapter unless the context clearly requires otherwise:
(1) "Eligible toll facility" or "eligible toll facilities" means portions of the state highway system specifically identified by the legislature including, but not limited to, transportation corridors, bridges, crossings, interchanges, on-ramps, off-ramps, approaches, bistate facilities, and interconnections between highways.
(2) "Express toll lanes" means one or more high occupancy vehicle lanes of a highway in which the department charges tolls primarily as a means of regulating access to or use of the lanes to maintain travel speed and reliability.
(3) "Toll revenue" or "revenue from an eligible toll facility" means toll receipts, all interest income derived from the investment of toll receipts, and any gifts, grants, or other funds received for the benefit of transportation facilities in the state, including eligible toll facilities.
(4) "Tolling authority" means the governing body that is legally empowered to review and adjust toll rates. Unless otherwise delegated, the transportation commission is the tolling authority for all state highways.