What working title did Pixar use for the film that became Cars?

Pixar used Route 66 as a working title for the film that became Cars.

The early title reflected the project's strong connection to the historic American highway and the small towns whose economies changed after interstate highways diverted traffic. The eventual title, Cars, is much broader and more direct, but the Route 66 influence remained central to the finished film.

The movie's setting, road-trip structure, and characters were shaped by research trips through the American Southwest. Radiator Springs combines visual and cultural influences from real Route 66 locations, while the story contrasts the old road with faster modern transportation.

Route 66 is not the final title and should not be confused with the film's fictional town or with the Cars Toons series. It is cited as an early working title during the film's development.