In Pixar’s Cars 3, Cruz Ramirez uses dirt for her final training with Lightning McQueen.
Lightning initially trains Cruz at the Rust-eze Racing Center, but the high-tech program does not produce the results he wants. He later takes her to the Thomasville area, where they study the techniques of Doc Hudson and his old racing rivals.
Dirt becomes important because it lets Cruz develop control, balance, and confidence away from the polished surfaces of modern race tracks. Lightning’s own experience on dirt helps him understand that Cruz has abilities the simulator-based training failed to reveal.
The dirt-training sequence also changes their relationship. Lightning begins as Cruz’s instructor, but he increasingly recognizes her potential as a racer. The film’s climactic events at the Florida International Super Speedway show how that preparation affects the future of the team.