mowermech wrote:
North Carolina State Laws, Para. 20-124 (f):
"Every semitrailer, or trailer, or separate vehicle, attached by a drawbar or coupling to a towing vehicle, and having a gross weight of two tons, and all house trailers of 1,000 pounds gross weight 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 subsection (e) of this section and shall be of a type approved by the Commissioner."
I have never found out which (if any) "types" of auxiliary brakes are "Approved by the Commissioner".
I'm not aware of any standard passenger vehicle that is
not equipped with brakes of a type approved by the federal DOT and/or NHTSA, and typically by reference by each state. The auxiliary brake
controllers typically used in the RV market however, apparently do not require such approval.