Many of the comments here seem to be missing the point. It is an object moving into the path of the car, and if the safety systems work as advertised, it should avoid that object. Whether it's a person, shopping cart, bike, go kart, etc. doesn't matter.
It's also worth saying that the human brain can almost instantly do a fight or flight calculation as to whether it's a moose or a plastic bag floating by taking into account the motion, and it's reflective properties etc.
This task clearly is very very hard to do, but tough shit: if you can't safely control a megajoule of kinetic energy coming down the road your computer shouldn't be given the benefit of the doubt.
