What does Hannah remember about her mother's accident?

Hannah remembers the big bang when the car hit her mother. The next moment her mother was lying on the cold, hard ground in the beam of the car headlights. Her arms and legs were all twisted. Her skin was white and blood was flowing from little cuts in her face. The man who was driving called emergency services and gave Hannah a coat while they waited for the ambulance. He left just before the ambulance arrived.