You have to understand I worked in a Psych hospital as a CNA and took many courses in the field. I am not health care professional in the field. I am going by my own experience with similar happenings
Many times when you feel guilty about a loved one passing away, you feel you should have done something. it could mean:
1.to prevent it:
2.to say something that wasn't said.
The car means he is on his way... somewhere. Pulling away means you have not said what you wanted to say.
When you dream you dream in too ways (recent discoveries). First a lot of images go into your mind trying to make sense of them all. Then the mind takes those images and tries it's best to make sense of them. Int his way you work through events and happenings in your own way.
The road could mean: where he was and were he went.
The car could mean: Something that you understand when someone goes places
The event: You wanted to say something, by calling out. But you feel it didn't get said because he might not have seen you or you feel you should have said something, but you were to late.
It's possible that that is what it means.
Now, having this bothers you. Or you wouldn't put it down. So I will go further. What I am to say might not be the answer. I am not trained for this.
Saying what you wanted to say might help.
1. We have beliefs that those who have departed can here us... or they can her us because we have a connection. You are half him. So there is a connection there. If you have something to say to him, when you have that dream, say what you want to say to him... figure it out ahead of time. Then just tell him.
This is the way I look at it. Religion or not...and I an Christian... THe energy of your father is still around. Energy is concerved always in the universe. That means a part of him is still around. If you say to him "out there" things you had wished to tell him, or just open up a dialoge every now and then... you can let him know the things your felling.
That might help with the dreams...