In the drawbridge scene, when Snowman gets out of his rig, there is no car ahead of him. In the next shot, Bandit is in front of him and there is no trailer. In the next shot, the trailer is attached. In the next shot, Bandit is behind the trailer. In the next shot, he is in front of the tractor. In the next shot, he is behind the trailer but in front of another rig, which was not shown in any previous shot. Some shots later, the bridge is down and going up, when before it was up.
Throughout the movie, Sheriff Justice drives a 1980 Pontiac Bonneville. When Mean Joe Green turns it over, when his car goes into the river in the drawbridge scene, and when the Bandit jumps over it in the Miami warehouse parking lot, the car is a 1976 Bonneville.
Sheriff Justice is in two different cars during the scene when he is chasing the Bandit through the roller-coaster. This is denoted by disappearing and reappearing damage to the front end of Sheriff Justices car.
During the "World's Biggest Game of Chicken" one of the red police cars is crushed between 2 trucks. When it emerges it continues for a short while then falls on it's side. After it has fallen you can see a cable and pulley in front of it which obviously pulled it along
As the Bendit prepares to leave after setting up the diversion with Terry Bradshaw, you can see two crew members and a piece of equipment reflected in the driver side door. Look for a man wearing a blue wind breaker jacket and sunglasses to be reflected in the car.
When Buford's sheriff's car drops into the river from the bridge, it is clear that there is a mannequin placed in the driver's seat. The left arm is fixed along the driver side door, and never moves during the fall.
When Bandit tells Sheriff Justice he's out of bullets and drives off, jumping the car over the conveniently placed flatbed truck, it's glaringly obvious that there is a mannequin in the passenger seat where Sally Field's character is supposed to be.
When Justice first encounters the bandit, and talks to him through a loudspeaker, he does not push the push-to-talk button. If he had locked it in talk mode, it would have picked him up telling his son to shut up.