Auto-braking systems only operate a low speeds (below 15mph I think). There’s also the emergency brake assist systems that do operate a speed. They use front f

Auto-braking systems only operate a low speeds (below 15mph I think). There’s also the emergency brake assist systems that do operate a speed. They use front facing radar to detect objects you might be about to collide with, and increase the brake pressure assistance, so you still need to physically press the brake. But if the car thinks you won’t stop in time, then it’ll multiply your break input to try and bring the car to a holt fast enough. But, you need to provide the initial brake input, they won’t fire alone.