In Pixar's Cars, the highway identified near Radiator Springs is Route 66.
U.S. Route 66 was one of America's original highways, established in 1926 and running from Chicago to Santa Monica. The road became famous through migration, tourism, music, literature, and roadside businesses before much of its long-distance traffic moved to newer interstate highways.
Cars uses Route 66 as the historical setting for Radiator Springs. The fictional town represents communities that lost visitors after a bypass diverted traffic away from the old road. This gives the film a setting rooted in real American transportation history rather than an invented modern freeway system.
Radiator Springs itself is fictional, but its landscape and businesses draw on real Route 66 communities in states including Arizona and New Mexico. The film helped renew popular interest in Route 66 landmarks and roadside culture.