When a combination of vehicles has been licensed to a total gross weight of 80,000 pounds or when a three or more axle single unit vehicle has been licensed to a total gross weight of 40,000 pounds, a temporary additional tonnage permit to haul loads in excess of these limits may be issued. This permit is valid for periods of not less than five days at two dollars and eighty cents per day for each two thousand pounds or fraction thereof. The fee may not be prorated. The permits shall authorize the movement of loads not exceeding the weight limits set forth in RCW
46.44.041 and
46.44.042.