Agreed re: insurance reasons. That said, the phrasing of the event is interesting "...self-driving car hits municipal bus..." and (in article) "...self-driving car struck a municipal bus...", and the co-driver (and vehicle) is quoted as "believed the bus would slow or allow the the Google (autonomous vehicle) to continue.", sound a little "soft", more like "yeah, I think that's my fault". I don't have 'favourite to win', regardless. There's another article[0] that I didn't see earlier that does in fact accept at least partial fault, and additionally mentions that the software was updated as result of this event. Thankfully it seems to be a low-cost (in terms of injury and damage) event, but fascinating given the young state of autonomous driving.
[0] http://www.reuters.com/article/us-google-selfdrivingcar-idUS...