(a) A law or agreement of less than statewide application that is adopted by an agency or political subdivision of this state and that regulates motor carriers or commercial motor vehicles or the operation of those carriers or vehicles in the transportation of cargo across the border or within an area adjacent to the border by foreign commercial motor vehicles has no effect unless the law or agreement applies uniformly to an entire border commercial zone and only in a border commercial zone.
(b) This subchapter supersedes that portion of any paired city, paired state, or similar understanding governing foreign commercial motor vehicles or motor carriers entered into under Section 502.091 or any other law.