In Pixar’s Cars, Lightning McQueen is separated from Mack on Interstate 40. McQueen falls from Mack’s trailer while the transporter is traveling west, and the resulting chase leads him away from the highway and into Radiator Springs.
Interstate 40 is a real cross-country highway that broadly follows the path of historic U.S. Route 66 across parts of the American Southwest. The film later emphasizes Route 66 as the cultural and historical road linked to Radiator Springs.
Route 66 is therefore an important neighboring answer, but it is not the highway named for the separation scene. The distinction matters because Cars uses both the modern interstate and the older roadside route in its setting and themes.