Revealing mistake: If you look closely at the pen tip when Snowman is writing the note to Coors to send the bill to Big Enos Burdett, you can see that it is not in the writing position, it is clicked shut. (00:15:57)
Revealing mistake: In the scene where the Trans Am is hiding among the truck convoy, you can see that the vehicles are all on the wrong side of the highway, as if to let the camera vehicle travel on the normal side of the highway. Notice the missing westbound lanes in the background as the vehicles are pointing directly to the viewer's right...then the lanes are back when the vehicles are shown from the front or rear.
Revealing mistake: When Frog makes her "We're going 110." comment, they then show a close-up of the dash-board. Even though the speedometer does show them to be going 110 (albeit km/hr, not miles), the ignition key is in the 'off' position, and the 'amp' gauge shows '0'. This is a clear indication that the engine was not actually running during this shot. (00:21:00)
Revealing mistake: In the chase scene with the cop taking a "10-100," the patrol car loses control and goes backwards into a lake. But if you look closely as it plunges in, you can see the backup lights lit, which is impossible if the car was in drive.
Revealing mistake: When Frog says "We're going 110" she's misreading the speedometer. It shows that they're going 110 kilometers/hr, which is 70 miles/hr. Also, the ignition is turned off and the oil pressure and temperature gauges read far lower than they would if the car was actually going 70mph. There's also far too much dust on the dash and gauges for a brand new car that hasn't been on any dirt roads yet. (00:21:00)