[Mawr]

> The stopping distance at 25mph is 30 feet,

Stopping is nice, but not the entire point of braking. The lower the collision speed, the better.

> Human reaction time is about 750ms

No. Human reaction time is around 250ms on average. What you point to is the time it takes to react to an unexpected stimuli. The number I've seen quoted is about 1s. But that assumes a completely unexpected event that you're not prepared for at all.

So if you're mindlessly passing a school bus at 25mph, then a 1s delay is expected. But if you're doing so with your foot covering the brake while hyper focused on reacting to any sudden movement in front of you, you can do much, much better than 1s. Of course, at that point you might as well drive correctly by slowing down.