
Continuity mistake: When Phil has the groundhog in the truck at the quarry and is about to drive over the edge, Rita's hair is disheveled and sticking out all around her head. But after Phil has driven off the cliff and she's looking down, it's all pinned neatly in place.
Answer: We know the police car survived because unit 2 is the car that followed them onto the tracks, and unit 2 is also one of the cars present when they are stopped (though it came from the wrong direction). The movie doesn't explain how the car survived so it is left to the viewer's imagination.
jimba