In Pixar's Cars, the historic racer and former Piston Cup champion who serves as Radiator Springs' doctor is Doc Hudson.
Doc initially appears to be the town's stern judge and medical authority. He sentences Lightning McQueen to repave Radiator Springs' damaged main road, but his deeper connection to racing is revealed when McQueen discovers old newspaper clippings.
Doc was once the famous Hudson Hornet, a champion who won three Piston Cups. A crash ended his racing career, and he became disillusioned when the racing world moved on without him. His story helps McQueen understand the importance of humility and community.
Doc Hudson was voiced by Paul Newman, whose own reputation as a racing enthusiast added resonance to the role. The character is based on the real Hudson Hornet, a car associated with early-1950s stock-car racing success.