When operating within the established construction or maintenance project limits as specified in the highway construction plans or contract documents, no permit shall be required for movement across, upon or along any highway of oversize or overweight vehicles of the department or a contractor or other person currently involved in the authorized construction or maintenance of the highway. Movement under this section is not authorized upon a bridge posted under section 4902 (relating to restrictions on use of highways and bridges) unless the posted bridge is currently being reconstructed or maintained.
75 Pa.C.S. § 4963