Re: How does your brain percieve the difference --
"How does your brain perceive the difference --
-- between a blowing plastic bag in the road and a running child in the road?"
I understand your point, but applying the brakes seems like a reasonable response under both of these circumstances until they really can tell the difference.
Also, I suspect this is generally something that people are not very good at either. Maybe we can't tell. Plenty of children darting into roads get hit. Plastic bags impacts aren't recorded...
Additionally, I'd hope that the software can track 'unknown objects' while they are still on the sidewalk (or when they have JUST left the sidewalk ie. 100% awareness), such that the car could slow down in anticipation of the plastic bag / child running into the street. I.e. less emergency braking.
Also, automatic cars might Actually drive fairly slowly in an urban setting e.g. 15-20 mph. In the UK we have signs that say 20 is plenty. So while I wouldn't want to get run over at 20 miles an hour (fatality 5% chance), it's WAY more survivable than being hit at 30 mph (fatality 45%). And hopefully the car would be stamping on the brakes anyway.
Either way, automated cars erring on the side of caution in an urban setting seems reasonable, and who's to say that people are any better at not hitting children than plastic bags.