The fact set is straightforward. The car was in the rightmost of three through lanes approaching an intersection where it intended to make a right turn. There is no formal right turn lane, but the rightmost lane is amply wide for parked cars. As there were none near the corner, the right hand side of the lane acted as a de facto additional right turn lane.
As the Google car approached the intersection the light was red and there was a line of cars in the lane ahead of it. It moved into the far right side of the lane and continued toward the corner. It turned out that its way was blocked by a pile of sand bags around a storm drain. It therefore waited for the light to turn green and the cars lined up in the lane to clear out. It then merged back into the main lane. Sadly, it mistakenly assumed that the bus coming through in the same lane would stop for it. Why, I cannot imagine. Wackiness ensued. Fortunately, this was all pretty low speed, so the wackiness was of limited extent.
I am not a lawyer. I am but a lowly paralegal, and therefore have no legal opinions whatsoever. I also work on traffic accident cases all the time. Were I to have a legal opinion, it would be that the Google car is unambiguously at fault.