My gripe with this argument is that even some humans can have a reaction time to at least start braking under these circumstances, I don't mean all drivers but as an example: I raced go-karts (just as an amateur but took some lessons and also some racing classes in cars with 300 hp) and sometimes my reflexes while racing were surprising, even for myself, narrowly avoiding collisions at 100+ km/h in tight circuits. With that said I'd have thought that sensors and computers could be much faster than even my trained reflexes.