A weighmaster shall not certify to the gross weight of a vehicle whenever all of the following conditions prevail:
(a) The scale is located at the site where the vehicle is loaded.
(b) The vehicle is weighed before entering a highway.
(c) The vehicle’s gross weight exceeds 80,000 pounds, unless a special permit authorizing a greater gross weight for the vehicle has been issued pursuant to Section 35780 of the Vehicle Code.