What information does Nick discover about the accident when he is talking to Gatsby?

While talking to Gatsby, Nick discovers that Daisy was driving the car.

Was Daisy driving?”

“Yes,” he said after a moment, “but of course I’ll say I was. You see, when we left New York she was very nervous and she thought it would steady her to drive — and this woman rushed out at us just as we were passing a car coming the other way.