Pretty sure the requirement for supplemental braking system is established by the state. Ive checked the code books for California and come up with a couple of different answers generally if the vehicle is 3000lbs or more,I have also understood it to be 1500lbs, but, is a toad a trailer? Ive been told no, the toad does not need a braking system, just a break away system. Generally in those gray areas,( and there will be plenty who say there is no grey area), however for me, I installed a supplemental braking system, I rest easier knowing im doing the safe thing.