If a pedestrian - or any other 'uncontrolled' road user - walks out into the road within 20 feet of a car approaching at 70mph, there's no technology on Earth can save them. It's "violating the laws of physics, Cap'n". Or is it? Increase the coefficient of friction between tyre and road, so that the car can decelerate at 8g, perhaps?…
In the scenario you describe, I would bet on the car outperforming a human driver every time.
A Tornado or F-111 bomber can fly 30m above the ground at 400mph because their onboard terrain-following guidance systems have millisecond reflexes and unbroken concentration, and those systems were developed in the 1970’s. In fact, the limiting factor to how low and fast they can fly is the g-tolerance of the pilots on board.
Electronic Brake Assist is already out there – if a driver brakes quickly and fast enough (or a sensor sees an imminent collision), the car recognizes it’s an emergency and boosts the brakes to the max – apparently, most drivers simply don’t press the brake pedal hard/fast enough. It saved my bacon once

. It was quite creepy feeling the brake pedal drop to the firewall by itself...and then slowly rise back up after I had put my foot back on the accelerator
