Visible crew/equipment: When David Mann stops off at the reptile lady's place, he enters a phone booth to call the police. When he's inside, you can see a perfect reflection of Spielberg. Look how young he looks.
Continuity mistake: At the end of the film, David Man comes to a dead end, so he spins the car around and waits for the truck to appear. When the truck appears from over the hill, take a look at the very next shot of the truck from the front, and you will notice that the large exhaust on the side of the truck has moved from left to right and back to left again. (01:21:00)
Visible crew/equipment: Near the end of the film, while Dennis Weaver is finally starting to get a good lead on the truck, the top of director Steven Spielberg's head is visible in the reflection of the back seat in the rear-view mirror.
Continuity mistake: When David Mann crashes his car against the truck near the end of the movie, the car's frontal bodywork inexplicably returns as brand new in one shot and back smashed again.
Chosen answer: The movie opens with him in downtown Los Angeles, California, so he's probably from there or somewhere in Southern California. He's heading to Bakersfield, California, which is north, about 2 hours away. In the short story, he's heading to a client in San Francisco. However, in the film he gets off the main freeway running from LA to Bakersfield (IH-5) and takes Highway 14 towards Canyon Country.
Bishop73