As you can see, it all depends on the circumstances. There are other states that have limited requirements on towing Trailers and brakes. I just listed some that were part of this discussion. Doug
MASSACHUSETTS
Every trailer having an unladed weight of more than 10,000 lbs. shall be equipped with air or electric brakes.
note that it is 10,000 lbs
OREGON
Independent braking system not required, but combination of vehicles must be able to stop within legal limits. Every motor vehicle and combination of motor vehicles, except motorcycles and mopeds, shall at all times be equipped with a parking brake system.
TEXAS
A trailer or pole trailer is required to have brakes if its gross weight exceeds 4,500 lbs. A trailer with a gross weight between 4,500 lbs. and 15,000 lbs. is not required to have brakes if it is towed at a speed of not more than 30 mph.