In the movie where Lightning ends up in Radiator Spring, he discovered that the town was not always the run-down town that it was. The town used to be a popular stopover until the I-40 or Interstate 40 was constructed bypassing the town. There also resides Doc, a three time Piston Cup winner who retired because of an accident.
The movie is actually inspired by many Route 66 places, locations and stories. One recollection by a barber in Route 66 said that the business in their town literally withered when the Interstate 40 was constructed.