A. Except when restricted by bridge capacity in § 46.2-1104, the vehicle size and weight limitations contained in Articles 14 through 17 (§ 46.2-1101 et seq.) of this chapter shall not apply to (i) any farm machinery or agricultural multipurpose drying unit when such farm machinery or agricultural multipurpose drying unit is temporarily propelled, hauled, transported, or moved on the highway by a farm machinery distributor or dealer, fertilizer distributor, or farmer in the ordinary course of business or (ii) firefighting equipment of any county, city, town, or firefighting company or association. Any farm tractor or agricultural multipurpose drying unit wider than 108 inches, however, which is so propelled, hauled, transported, or moved on the highway shall be equipped with a safety light of a type approved by the Superintendent of State Police. The light shall be plainly visible from the rear of the tractor or agricultural multipurpose drying unit. No firefighting equipment of any county, city, or town, or firefighting company or association may be operated on any Interstate Highway System component if it exceeds the weight limitations in § 46.2-1127.1. No overweight farm machinery or agricultural multipurpose drying unit under this section shall be operated on any Interstate Highway System component if the vehicle has:
1. A single axle weight in excess of 20,000 pounds;2. A tandem axle weight in excess of 34,000 pounds;3. A gross weight, based on axle spacing, greater than that permitted in § 46.2-1126; or4. A gross weight, regardless of axle spacing, in excess of 80,000 pounds.