Earlier quoted context omitted.
The counterargument to this is that since humans reach acceptable safety levels with vision only, it must be possible to do self driving with vision only. That said, augmenting vision with other methods does seem like a no brainer for better performance.
> The counterargument to this is that since humans reach acceptable safety levels with vision only 100+ car pileups in Southern California checking in to provide a counterexample. The patchy fog in Southern California on I-5 can go from "not too bad" to "can't see your own hood" in a matter of seconds. Radar is going to catch hazards WAY before a human will.
This leaves the question of moving to radar, but for precise resolution well ahead of the vehicle you need microwaves and a lot of power, I would guess - which reduces the vehicle's range. For all I know you might parboil passersby, too. One old Mig had a radar that would kill and roast rabbits on the runway as it took off, but that's a much different use case, of course.