The ‘world building’ in Cars, like most fantastical settings for children’s media, is just setting up jokes with no concern for internal consistency or thought about the implications. The audience isn’t supposed to think about it!

That said, this was pretty funny as an example of thinking too much about it is the path to madness.

and it’s one of tthe most loving cartoons by boys. To this day I get asked to make Cars cakes for 5yos