Factual error: When Timmy (the kid who gets crushed by the glass slab) is at the dentist, the tube on the water tank comes off and water spurts out. That tube is the water intake, so if it were to break of it would be sucking in air, it would not be spurting water out.
Revealing mistake: At the beginning of the movie, (outside Kimberly's house when she says, "We're gonna go meet the guys") one of the extras in the background (he is clipping the hedges) keeps looking at the camera. [This was pointed out on the DVD].
Plot hole: The truck was in front of all of them when they turned on with the green light, but it passes them when they are stuck with the red truck. So the crash happens moments past the light, so they would all be way past that point on the interstate.
Character mistake: If Clear was worried about her safety, why was there a TV monitor in her room that could blow glass or catch fire?
Visible crew/equipment: When we see Kim's vision, there is a shot of the car going down the highway. In some shots you can see tyre marks from the camera car on the hard shoulder.
Visible crew/equipment: When Buek and Kim are at the gas station a crew member can be seen in the truck's paintwork.
Character mistake: Although Dr. Kalarjian said that there is a "code blue", which means a patient requiring resuscitation or other immediate medical attention, she wanders over there without rushing at all.
Suggested correction: When she was getting closer, she started rushing more. It took a while for her to get there but maybe that was just done to fool the audience. Kimberly did think she was going to kill Isabella after all.
Revealing mistake: When they are all in the van to meet the pregnant woman, tyre marks from the camera car are visible.
Visible crew/equipment: During the highway pile-up Rory's car barrel rolls in slow motion over an unmanned camera, during this shot you can see the cannon on the bottom of the car used to flip it. Then in the very next shot you see the car barrel roll from a different angle and the unmanned camera from the first shot is visible. It doesn't look like a typical camera, its disguised as debris, but it would not be there had the slow-mo shot not been filmed.
Revealing mistake: In the pile-up scene when Kim's car starts to flip, you can see that the driver side window is removed and placed with plastic wrap, probably to protect the driver. This is on the DVD.
Continuity mistake: Sometime in the middle of FD1 Alex is walking to Clear's house and Clear says "It's almost Autumn." Alex replies "It's only the middle of June." which means that it must be June. But in FD2 when the main characters are in Kat's car talking about cheating death Kat says "Last May I was..." referring to being on the bus that killed Terry Chaney. It was only one day before Terry got hit by a bus when Alex went to Clear's house. So is it in May (like Kat said) or June (like Alex said)?
Continuity mistake: The position of Tim's hands change when he is about to leave the police station.
Visible crew/equipment: There is a fluffy mic visible in the car that Kat is driving when it crashes into the haystacks.
Revealing mistake: At the beginning of the film, even though the sky is cloudless and clear blue, the streets and highways are uniformly wet, as if a storm had just swept the area. Then, even though all of the vehicles on the highway are raising clouds of wet spray, none of the vehicle windshields are splattered with moisture, and none of the vehicles are using their windshield wipers. In fact, the only time we see a woman use her windshield wipers is when the guy throws a lit blunt onto the woman's windshield and it catches some dry leaves there on fire. So, in summation, dry leaves catch fire on the windshield of a car in spite of heavy road spray on a wet highway on a cloudless day. Multiple inconsistencies.
Revealing mistake: When Rory gets sliced by poles, if you look close the poles can be seen hitting an invisible pole then bounce on the ground.
Visible crew/equipment: In the pile-up scene when Eugene falls off his bike and crashes into the log you can see what seems to be a crash pad. After he has fallen and hits the log, the bike crashes straight into him. If you look closely just above the log you can see the crash pad.
Continuity mistake: In the pile-up scene, when Kimberly's car flips over, you can see the rear-left wheel breaking apart, then in a quick shot from a different point of view, it has its four wheels, and the very next shot, the wheel is breaking apart again.
Factual error: In the scene with the defibrillator it shows on the trace that her heart rhythm is asystole. Defibrillators only work with shockable rhythms i.e. VF (ventricular fibrilation) or pulseless VT (ventricular tachycardia). Using one on an asystolic patient would have no effect at all.
Revealing mistake: When Kimberly's car gets flipped around a bunch of times, the dummie's limbs flopping around are quite obvious.
Deliberate mistake: When Kimberly is being revived, it's obvious that they are using a defibulator. But when Kimberly finally comes to and is covered by a sheet, you can see she has a bra on. This is impossible to have because you need direct contact with the skin in order for it to work. And the machine would start the heart working if it was lower on her chest.