> It’s much more difficult to prepare self-driving cars for unusual circumstances — pedestrians crossing the road when cars have the green light, cars making illegal turns. Researchers call these “corner cases,” although in city traffic they occur often.

These are difficult to deal with as human drivers too. This article is pretty light on details and basically pins the lack of progress on a couple of Tesla crashes. The thing is, regular people crash cars every day. I'd much rather share the road with self-driving cars than cars driven by humans. Especially with the advent of smart phones, not a day goes by that I don't see multiple people heads down messing with Instagram while driving.

This technology is a lot closer to reality than the article makes it seems I think.