As a matter of fact, the computer will know about the problem long (hundreds of milliseconds) before you see it and will already be reacting.
The idea that you could react faster or make a better critical decision than the computer is sort of funny actually.
I agree that a computer will certainly be able to react faster in the event of a sudden unexpected obstacle, but what about my human ability to see children playing near the road or someone who isn't looking my direction but hasn't actually stepped off the curb? I can preemptively slow my vehicle just-in-case. A human can quickly detect things about their surroundings that computers aren't yet capable of.