Deliberate mistake: At the start of the film when the commentators are explaining the tie situation between the 3 cars the green arrow to the car is out of alignment and misses the car, instead pointing at the track. Pixar Creative Director, Jay Ward, who is this film's team manager (as well as art coordinator) has stated that this was deliberately done as a joke, for fun. It's a little bit off, in the same way that Chick Hicks is a little bit off. This is the video with Jay Ward explaining: https://youtu.be/ZkJre-eC-zE?t=25.
Chosen answer: Nope, nothing official was ever said. There are very few truly original film storylines these days; a close examination of most films would allow one to swiftly note plot similarities to any one of a number of preceding movies. Both Cars and Doc Hollywood fit neatly in a very standard storyline of an outsider coming into an unfamiliar cultural group, which they learn to appreciate and benefit from, while their presence likewise benefits the group they encounter. While the two are unusually similar, no comment on the subject was ever made.
Tailkinker ★