A video was just released a few hours ago of one of Google's self-driving car colliding with a bus. The incident actually happened on Valentine's Day, 2016 in Silicon Valley's Mountain View.
The dash-cam footage is from the bus that was hit by the self-driving car, which was released by The Santa Clara Valley transportation authority. In the footage, you can see the white car on the right side, rolling to the left. The car may have overestimated its timing, because it tried to get ahead the bus far too late, bouncing off the side of the bus.
According to the Telegraph, this is the first time one of the cars has caused an accident in public. Google has submitted an accident report to the California department of motor vehicles. Thankfully, nobody was hurt.