(a) The provisions of this subchapter, except as specifically limited in this subchapter, shall apply to the transportation of passengers or property by motor carriers over public highways of this state and the procurement of, and provisions of, facilities for such transportation.
(b) Provided, nothing contained in this subchapter shall be construed to authorize the regulation of intrastate fares for the transportation of passengers by bus by an interstate motor carrier of passengers over any routes authorized by the Interstate Commerce Commission [abolished].
(c) Provided, further, nothing contained in this subchapter shall be construed to abrogate the laws of this state or any authority of the State Highway Commission with regard to the routing of hazardous materials.