Whose fault? Engineering control or Administrative control?

This afternoon while I was having lunch, there was an accident occurred in front of the restaurant. A Vios bang with a Harrier. Quite serious because the front wheel of the Vios seems like came out from the car body already. The 2 drivers were arguing on whose fault. Everybody was blaming on the opposite party. The cross road without stop-look-go sign. So, whose fault was that? Just think about this???