The whole dream gives me the feeling that crossing this bridge is a transition, and you will transition from your family to your boyfriend's life. But your parents were in your car, so the car fell off the bridge. But neither you nor your parents were injured, which means that you chose your parents' family. I have a guess here. Did you break up with your boyfriend because of your family?
My suggestion: You should divorce your family of origin, which is good for your independence, your future marriage, and especially for your father.