i dont remember how to do the spoilers thing so if you want to see the movie, dont read the following:
the father falls asleep at the wheel of their car, it cashes into another car carrying the woman and child (woman in white, child in her arms). the man in the black car is the person who reports the crash. they try to make you wonder wether the surviving girl was dreaming everything that happened or if the man in the black car set it up after he killed them