The working title of Pixar's Cars before release was Route 66.
The early title reflected the film's strong connection to the historic American highway and the roadside communities that inspired Radiator Springs. Pixar later changed the title to Cars, a shorter name that emphasized the movie's vehicle-centered world.
Route 66 runs from Chicago to Santa Monica and became famous for connecting communities across the United States. Its decline after the construction of interstate highways helped shape the film's story about a once-busy town losing passing traffic.
The title change did not remove Route 66 from the finished movie. The highway remains central to Radiator Springs' identity, and real landmarks and roadside architecture influenced the film's environments and locations.