For the people confused by this movie...

I watched this recently and also watched the movie "Dead End" Which essentially has the same plot (seemingly insignificant accident at beginning, weird events take place after accident, everyone dies save one).

Here's my take on both films (and any other like it):

They aren't dreams so to speak and really they aren't in Limbo either (kind of). I believe that at the beginning when the accident happens the souls of the people don't realize that the body is dead. Anyone who knows anything about ghosts know that typically, ghosts don't know they are dead until it's revealed to them or "shocked" into them. I'm pretty sure this is what is going on in both these movies. through out the movie the "soul" of the person carries on like the accident was no biggie and the strange things that happen is like nature or God's way of trying to tell the soul that it shouldn't be there. That the body is dead. If you think about what typically happens in these movies, where the people die in similar fashion through the movie as they are shown to have died in the ending (like burning to death AKA the car caught on fire or head trauma of sort AKA going through a windshield or something from the backseat coming up to hit them for example). The part where the coroner had went to cut her then backed away was explained in the end where they showed him going to cut her dead body but then the phone rang. The part where they are in the caskets thinking they are going to be buried alive was in actuality them being prepped for burial but the soul or "ghost" of the person didn't realize it was dead so it thought that someone was trying to kill it. With any "ghost" type story, once the ghost or soul realizes it's dead that's when things get pieced together and the soul or ghost can rest. In the movies where there is a survivor, the survivor is going through in their mind what happened to their family or friends but the mind is warping it a little due to the trauma of the accident. that's just my personal take on it after seeing quite a few films with this type of story line. They all seem to have this same "soul not realizing it's body is dead" type plot to it.