Factual error: The train in the joyride scene is a Burlington Northern locomotive, which would never be found in Pennsylvania.
Continuity mistake: When Phil is playing the piano at the party, he is wearing a pair of RayBan Wayfarer sunglasses. When he takes them off and sets them on the piano, they have turned into RayBan Baloramas.
Other mistake: On the second day, Phil did his same tasks at about the same time as the previous day, so everything lining up the same made sense. However, on day 3, he quickly rushes out of his hotel, avoiding interacting with most of the people he did before and gets to the street with the beggar much sooner than he did before. Yet Ned still is there crossing the street and sees him exactly the same as before. However with Phil having skipped so much he would have gotten there and passed that spot a good while before Ned would have gotten there, and they should not have had the exchange again on day 3. Same thing for when he arrives at the Groundhog Festival, with Rita greeting him like he's late. But he would have gotten there much sooner this time.
Other mistake: Focusing on the clock as it turns to 6:00, one clock has a visible gear in the middle of the numbers. At other times, no gear.
Continuity mistake: When Ned first calls out to Phil, the Gift Shoppe store behind him has a sign in the display window saying "OPEN SUNDAYS 12 to 4", and a white poster in the door window. The remaining three times Ned calls out to Phil with that background, the Open Sunday sign is gone, and the poster in the door has changed to a smaller red sign. Also, vehicle positions have changed slightly, and the black truck's tire sidewall on the left changes position between first and remaining scenes. (00:10:20 - 00:21:25)
Other mistake: In the opening scene as Phil is walking from the blue screen to the desk, a clock is visible over the top of the camera and it reads either 12:20 or 1:20 (the hour hand is too motion blurred to tell which). The broadcast is supposed to be at 5pm. (00:01:40)
Audio problem: When Phil is building his final snowman, Rita says, "Why can't I look?" but her mouth does not move. (01:32:50)
Continuity mistake: A green BIC lighter can be seen standing on end to the right of Phil's plate in the diner, between the plate of flapjacks and plate of eggs. In the next shot, in which Phil drinks directly from the coffee pot, the lighter has vanished. (00:35:10)
Continuity mistake: Towards the end of day 3 when Phil is drinking at the bowling ally, Gus says he pegs Phil as a glass half empty kind of guy. Phil is looking partly in his direction to his own left when he's saying this. When the camera cuts to a close up, Phil is looking straight ahead and then turns his head.
Continuity mistake: After Phil gets done with the weather report and then talking about his plans for the next day, he goes off to the side talking to some other men. He looks back and sees Rita playing with the blue screen. She looks over to her right at the TV which turns her head to the left of the camera. But then it suddenly cuts to what the TV is seeing and she's looking straight ahead, which means she'd be looking directly at the camera, and not the TV.
Continuity mistake: When the truck goes off the cliff in the quarry, we see it falling in a close shot, then it changes to a wider shot, except the driver's side mirror in the close shot is folded out, while in the wider shot it is folded in. The powder on the tires is also different. (01:03:20)
Continuity mistake: In the opening scene Phil is doing a weather report and is wearing a wireless mic on his vest. When they go off-air he jumps up and two seconds later the wireless mic is gone, neither on his vest or in his hands. Taking off both the mic and the transmitter would take longer than two seconds. (00:02:30)
Continuity mistake: When Phil kidnaps the groundhog the TV van has two intact headlights as it begins to chase Phil. When the van skids to a stop at the quarry, the right headlight is missing as if it had an accident.
Continuity mistake: When Phil wakes up for the third time he immediately runs out of the hotel without speaking to anyone in order to get to Gobbler's Knob faster but when gets outside the piano teacher is already walking across the street. She shouldn't already be there if Phil went straight from his room to the street.
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