In addition to other permits provided for in this article, the Commissioner, upon written application by an electric utility as defined in § 56-576, shall issue a permit authorizing the electric utility’s operation of vehicles used for the construction, operation, or maintenance of electrical facilities and infrastructure upon the highway at gross weights exceeding those set forth in § 46.2-1126. Permits issued hereunder shall specify that vehicles with two axles may have a maximum gross weight of no more than 48,000 pounds and a single axle weight of not more than 24,000 pounds and that vehicles with three axles may have a maximum gross weight of not more than 60,000 pounds and a single axle weight of not more than 24,000 pounds and a tandem axle weight of not more than 40,000 pounds. The fee for such permit shall be as provided in § 46.2-1140.1. The permit shall not designate the route to be traversed nor contain restrictions or conditions not applicable to other vehicles in their general use of the highways. However, no such permit shall authorize violation of any weight limitation applicable to bridges or culverts, as promulgated and posted in accordance with § 46.2-1130. Nothing contained in this section shall authorize any extension of weight limits provided in § 46.2-1127 for operation on interstate highways. Each vehicle, when loaded according to the provisions of a permit issued under this section, shall be operated at a reduced speed of 10 miles per hour slower than the legal speed limit on any highway with a speed limit above 30 miles per hour.