In the scene where Roy L. Fuchs (Jack Warden) walks up to Rudy Russo (Kurt Russell) and Jeff (Gerrit Graham) as they are finishing shoveling dirt over the spot where they buried Luke, Graham didn't have any lines and kept pestering Robert Zemeckis and Bob Gale for lines. Finally, he just decides to repeat whatever Russell said to Warden. Apparently, Warden was unaware of what Graham was doing, thus his line "What're you? A fuckin' parrot?". It was Warden's genuine annoyance at Graham, which worked so well in the scene that it was included in the final cut.

The reason Used Cars was made at Columbia Pictures was that Universal Pictures passed on this, and since the head of Columbia had once sold cars, he understood this right away.

According to Bob Gale in the Blu-ray commentary, executive producer Steven Spielberg was appalled by Rudy Russo's line about President Jimmy Carter: "Hey, he fucks with us..." Spielberg was a supporter of Carter. Robert Zemeckis and Gale refused to remove the line, because where they came from, (Gale is from Missouri and Zemeckis is from Chicago) politicians are (in their opinion) corrupt.

In the scene in which Gerrit Graham's character starts shooting at Roy L. Fuchs' cars for the commercial, real ammunition was used to shoot the windshields and the headlights.

Described by Robert Zemeckis as the Red River (1948) cattle drive with cars, the climatic chase scene was filmed in an abandoned and overgrown airfield east of Phoenix. Two hundred extras were recruited with the pitch "fifteen dollars a day, bring your own car, and be in a movie".