I couldn't find any other details about the accident, but it seems from the description like it was a side collision at an intersection. In order for that to h

I couldn't find any other details about the accident, but it seems from the description like it was a side collision at an intersection. In order for that to happen, it's likely that one of the vehicles had to violate a stop sign or red light. Note that the Autopilot isn't aware of these things (it won't stop unless a car in front stops). If the Tesla was the vehicle at fault, then most likely it was unawareness of this limitation on the part of the driver (or complacency thinking there wouldn't be any traffic).