In Pixar’s Cars, what highway causes Radiator Springs to be bypassed?

In Pixar’s Cars, Interstate 40 causes Radiator Springs to be bypassed.

Radiator Springs once prospered because traffic traveled through town along the old Route 66. When Interstate 40 opened nearby, most travelers stopped using the original road. The resulting loss of traffic damaged the town’s businesses and left Radiator Springs isolated from the main stream of highway travel.

This fictional history reflects a real pattern along U.S. Route 66. Modern highways redirected traffic away from many roadside communities, contributing to the decline of businesses that depended on motorists. Cars uses that history to explain why Radiator Springs is nearly forgotten when Lightning McQueen arrives.

A common mix-up is answering Route 66, because Route 66 is the historic road running through the town. Route 66 is the road that loses traffic; Interstate 40 is the newer highway responsible for bypassing it. The distinction is central to the town’s backstory and to the film’s road-trip theme.