All I know is that I can stop MUCH faster with TOAD brakes than without. I drove for a few years without and then added them. What a difference. I had a near accident shortly after installing the aux brakes and know I would have nailed the person who cut in front and then slammed on their brakes just ahead of me.
Every car since then has had aux brakes without exception. I like the security of those brakes. I will never know how many accidents the brakes may have saved us from. Small cost for peace of mind and a little better safety.