Computers can never be as good as a human at recognising and reacting to risk in our almost infinitely variable streets....They can't be brilliant at reading the road and conditions, anticipating what might happen, recognising developing hazards and all the rest of it.
Says you. Seriously, why not? Every time this sort of issue comes up with regard to AI, it turns out that there isn't some mystical human-only power that computers are metaphysically incapable of reproducing, rather it's just that we haven't yet properly framed the problem and described the capability that is required to respond to it.
The idea that humans are absolutely optimised for driving is belied by the number of accidents and injuries caused by drivers despite our having largely segregated motor vehicels from squishy pedestrians. Part of robots advantage is that they don't have to be "creative" about driving because they adhere to road laws, which massively reduces the degree to which they have to respond to hazardous situations and the speed with which they have to do it.