Every semitrailer, trailer, or separate vehicle attached by a drawbar, chain, or coupling to a towing vehicle other than a farm tractor or a vehicle not required to obtain a registration certificate and having an actual gross weight of 3,000 pounds or more, shall be equipped with brakes controlled or operated by the driver of the towing vehicle, which shall conform to the specifications set forth in § 46.2-1067 and shall be of a type approved by the Superintendent. Farm trailers used exclusively for hauling raw agricultural produce from farm to farm or farm to packing shed or processing plant within the normal growing area of the packing shed or processing plant and trailers or semitrailers drawn by a properly licensed motor vehicle but exempt from registration, shall be exempt from the requirements of this section.

“Gross weight” for the purpose of this section includes weight of the vehicle and the load upon such semitrailer, trailer, or separate vehicle.

This section shall not apply to any vehicle being towed for repairs, repossession, in an emergency, or being moved by a tow truck when two wheels of the towed vehicle are off the ground.