Did anyone bother reading the linked report?
It's not clear the author did more than skim it.
There's nowhere that says the car was "backing up." The car was "moving back" into the center of the lane.
Take a look at the StreetView for this intersection, heading East on El Camino Real as described in the accident report: https://goo.gl/maps/ibea7E9dMFv
That's a wide lane, enough for two cars if they're small. The Google AV moved to the right side of the lane in anticipation of the turn and possibly to get around other traffic. This is a very common move for meatbag drivers, though certainly questionable of an AV. Said AV encounters random sandbags blocking progress. AV waits for other drivers to pass, out of caution. When the area appears clear, AV begins moving toward the center of the lane (presumably forward) at 2 MPH to get around the sandbags. Meatbag bus barrels down the road at a comparatively quick 15 MPH and does not yield to the vehicle in front of it within its lane. There is a collision and the report describes it as the Google AV making contact with the bus.
The damage to the left front wheel indicates this collision may have been moderately more severe than a "fender bender."
Let's review what we've learned from this:
Richard Chirgwin needs to read his source material before posting.
El Reg needs to do a quick fact-check based on the simple, provided source material.
There were questionable decisions on the part of both the AV (2, by my count) and the bus driver meatbag (1, but rather egregious, by my count).
This was a low-speed collision with no injuries, thank God.
Google needs more time to improve its AV fleet safety before mass adoption. I, for one, am glad we have a sensible system in place for developing and testing these technologies.
EDIT: Worth thanking El Reg and Chirgwin for providing the sauce to begin with. Without sauce, I would not have been able to fact-check his statements and enjoy my delicious Righteous sandwich.