In Pixar's Cars, U.S. Route 66 is the real highway celebrated by the Radiator Springs sign and story setting.
Route 66 was established in 1926 and connected Chicago with Santa Monica, crossing a large portion of the United States. It became famous through automobile travel, roadside businesses, popular culture, and the migration routes associated with the twentieth century. The route was removed from the U.S. Highway System in 1985.
Cars uses Radiator Springs to dramatize what happened to many Route 66 communities after newer interstate highways diverted traffic. The town's businesses and landmarks are presented as remnants of a once-busy travel corridor. Lightning's forced stay lets him see the community as more than an obstacle on his way to a race.
The film's setting is fictional, but its geography and visual references draw heavily on the American Southwest. Route 66 therefore supplies both the location's identity and the film's central theme of remembering older roads and communities.