At the end of the movie the hitcher gets the gun from the guard he just killed in the transport van and shoots the officer in the front seat, but in reality the guard(s) in the back of the van would not be allowed to carry a gun when sitting next to a prisoner being transported.
The broken windshield of the 442 continuously changes throughout the movie. In some scenes it is slightly broken while in others it is completely shattered.
When Jim and Grace wreck down the ditch, a tree branch goes through the windshield that was broken earlier. But in this scene Jim smacks his head against the windshield and it's completely crack-free after being broken earlier.
When Ryder shoots Lieutenant Esteridge, he is holding the stainless steel Beretta model 92 that Grace took from Esteridge's holster. When Grace shoots Ryder, and he goes down, the gun is still the stainless 92, and the slide is closed. However, in the top down shot right after she shoots him, the gun laying beside him becomes a black Glock with the slide locked open.
In the shot when the family car passes Jim and Grace there is a little girl in a car seat. When they come on the car on the side of the road again, the little girl is not in the car nor in the car seat when Grace tosses it out. The little girl is never seen again through out the movie. In the special features section of the DVD is a clip of the news report of the family's murder - the girl's body can be seen in the rear with her brother's body. There are several differences between the news report and the events in the film: It states the family was found off highway 110, but in the film Grace and Jim drove the car to the diner; the children are said to be "between 8 and 12 years old", in the film, the girl is seen in a car seat, far younger.
When Jim and Grace break into the motel room, they enter room 12. However, when Grace comes out of the room, it is room 11. This is result of a deleted scene that can be viewed on the DVD, where Grace goes into the room 11, thru the connecting door, to find a couple murdered.
In the convenience store scene the guys says that Tatum is 15 miles away. Just before they get to the store there's mountains everywhere. There are no mountains or interstates anywhere near Tatum.
At the end of the movie Grace shoots The Hitcher in the head. During the overhead shot afterward, as the camera pulls back, Grace has the barrel of the shotgun in her hands- instead of the butt of the gun. This is due to the alternate ending that is on the DVD that shows Grace beating the Hitcher to death with the butt of the gun, when the shotgun is out of ammunition.
The tracks of blood on the station wagon father's chin change between shots when Jim sits in the back with him as he dies.
After Grace and Jim push the Hitchhiker out of the car, as soon as he is pushed, and shows him outside, you can see Grace leaning out and shutting the door. But when it shows them back in the car, she is still in the back seat, then moves to the front, and shuts the door, although she already did.
When Jim is filling his gas tank he says "pump 7" but when he returns out side he was filling at pump 3.
When the Oldsmobile 442 flies off the road, the airborne car crashes very hard nose first into the ground. Jim and Grace are not wearing seat-belts yet somehow they manage to remain seated without slamming into the dashboard or windshield.
When John Ryder hits his head on the 442s windshield, the whole shield is cracked, but when Jim wakes up in the morning, the driver's side half on the shield is now not cracked.
In the beginning after Grace is picked up from college she starts to change in the car. She puts jeans on, then in the next shot is wearing shorts.
After Jim wakes up from the nightmare and looks around for Grace he finds her standing next to a small cliff. The camera zooms close to her back and her arms and crossed, then it goes to a wider shot of her hands and they are in her back pockets. Then it goes back to the first shot with her arms crossed again.
When Jim pours the water on the windshield to get the dead bug off some water hits the camera lens.
When the car does the 360 spin, you can quickly spot the cameras and crew tied to the roof of the car whilst it's spinning.
When John rear ends the station wagon, the side rear glass breaks. In the next shot, the glass is unbroken.
Just after the scene where John Ryder kills all of the cops, Jim and Grace get out the car. As it is stopping you can clearly see that the tyre has worn away from where it was shot but then a different camera view shows the tyre still intact. It then disappears again.
During the car chase, a 2001 or newer model Crown Vic is spun sideways by the hitcher. However, when the same car is shown rolling over, the Crown Vic flying through the air is a late 90's model.
When Grace is in the bathroom pulling paper towels out of the dispenser, she stops and looks out the window, and sees John Ryder's red truck. She goes to lock the door and there is paper towel hanging out of the dispenser. When it cuts back, there are now no paper towels hanging down.
When Grace is in the police station, she is being questioned and then when the officer leaves the room, she walks around but then eventually leaves the room where she sees a German Shepherd rounding the corner, When it goes to a different view we see the dog going around the corner again, although it already has.
When Grace is in the police station and being questioned, the police officer leaves the room and Grace stands against the wall where we see a big bloody cut on her shoulder, when she walks to the mirror, the cut is gone.
When Grace has just been attacked by John Ryder and hides in the bathroom, she comes out to go look for Jim, she comes out of the room 11 even thought they originally went into room 12. When the camera view is on Grace coming out of the bathroom, the door is on the left of the screen and when she is completely out of the room and outside the door is on the right.
When Grace is in the questioning room at the police station she sees the door handle wiggle and we see that the handle is on the right side of the screen as if she would open it with her right hand and would open to her right side. When she opens it and peeks out she opens it as if the handle was on the left side of the door and it would open to her left.
When Jim is eating his hot dog outside the gas station, the size of it keeps changing from smaller to bigger between shots.
At the start of the film, they cast small shadows indicating its during the day, but when they join the highway, the sun is low and the sky is orange indicating sun down, the next shot shows bright blue sky and no shadows cast by the car.
When Grace and Jim are hiding in the shack from John Ryder after escaping the police station where they were interrogated, Jim asks Grace if she sees Ryder outside. Grace looks through the peep hole in the shack to look. There is a woman (probably a crew member) clearly visible in the field as the camera pans from right to left.
John Ryder makes the Ford Police Van flip and spin. However this van sometimes has American Taillight, sometimes has European Taillight.
In the car chase scene the helicopter pilot radios that another car (the one the John Ryder is in) is approaching. He describes it as a "Late Model" Trans Am, however it is a late 70's model, not a newer one.
Right before John Ryder shoots Lt. Esteridge in the head, Grace breaks the door off of he armored vehicle and lands on it. Then she screams, "No", but it is clearly visible that her mouth is not moving.
When the police are chasing Jim and Grace in the stolen police car, the rear driver side taillight of the stolen car is shot out as is the driver's side mirror. The taillight can later be seen unbroken along with the side mirror.
After John takes out the police cars and helicopter there is a shot of him coming up behind Jim and Grace as seen in the rearview mirror. However the rear window of the car was shattered, so there wouldn't be a clear view as shown in the mirror.
After almost hitting John Ryder in the beginning and then driving away, we can see it raining on the windshield of the car. However, at the speed they are traveling the water should be moving upwards on the windshield due to the air rushing against the car but instead travels downward as if the car was sitting still.