Did Julie cause the accident? (spoilers)
Can we assume that Julie found out about her husband's affair and so became suicidal and caused the car to crash? Aside from her apparent lack of grief, here is some evidence I think shows this:
1. Her attempted suicide at the hospital also involves a crash (the crash of the breaking window glass). Thus the implication that the car crash and her attempted suicide are somehow connected in a different way.
2. She seems to want to rid herself of any memory of her husband and daughter, including throwing away his music score for the unification of Europe. Thus the hint she wants to destroy any sense of "union" she has with her husband and daughter.
3. The cold way she releases the cat to kill the mouse and its babies. Like her cold way of killing her husband and daughter.
I.S. Oxford
"The books have nothing to say!"
-- Fahrenheit 451