Children’s entertainment is full of anthropomorphized objects and animals. To kids, talking automobiles are no more or less strange than babies who are bosses or teenage turtles who get mutated into ninja warriors. But to the parents and adults who watch the Cars movies with these children, their internal logic and rules are a source of endless fascination.

Pixar’s Cars debuted in 2006, with a premise of pure simplicity, in the mold of the talking toys and talking ants from director John Lasseter’s Toy Story and A Bug’s Life. Those movies, though, were set in worlds where humans existed; their societies of sentient playthings and insects existed right under our noses, just out of sight.

Cars was different. In its world, the motor vehicles, trucks, planes, boats, and “Pitties” — little forklifts whose tiny arms perform tasks the other cars cannot — are the only living creatures. If humanity existed, it had died out before the start of the film. But — and yes, this is an atypically dark premise for a Disney movie marketed to four-year-olds — humanity must have existed in the world of Cars at some point. Everywhere you looked, in every single frame, there was evidence that living creatures used to exist. After all, if there were never any human beings in Cars World, why do the cars have door handles?

A piece of concept art from ‘Cars 3’ (Courtesy of Pixar)

It may be a planet of cars, but like the Planet of the Apes, it is definitely Earth, or at least it was in the past. The cars speak English, and their map is littered with recognizable landmarks, from Route 66 to Hollywood. Things get even more confusing in 2011’s Cars 2, which takes its heroes, race car Lightning McQueen (Owen Wilson) and tow truck Mater (Larry the Cable Guy), out of the imaginary town of Radiator Springs on an international adventure with stops in Japan (where there’s sushi and wasabi, even though there are apparently no fish in Cars World), Paris (complete with an Eiffel Tower), and Italy (where the Popemobile is a beloved religious figure).

Based on the evidence onscreen, the cars have not built a vaguely human society; the cars have taken over human society. The U.S. flag is even visible in one scene in the first Cars. Did the cars overthrow our government, possibly as part of a coup d’Fiat? (Sorry.)

The Cars franchise has never offered an official explanation for any of these mysteries. But there is an internal document at Pixar that has never been shared with the public that answers some of these questions, and lays the ground rules for this unusual cinematic universe. It’s called “The World of Cars Owner’s Manual,” and it was written by Jay Ward, the Creative Director of the Cars universe. At the press junket for Cars 3, I put it to Ward: Where the heck do the cars in Cars come from?

Jay Ward (right) working with ‘Cars 3’ director Brian Fee. (Photo by Deborah Coleman / Pixar)

Ward offered this explanation (which he stressed was purely his theory, and not necessarily Pixar’s canonical reason):

If you think about this, we have autonomous car technology coming in right now. It’s getting to the point where you can sit back in the car and it drives itself. Imagine in the near-future when the cars keep getting smarter and smarter and after one day they just go, “Why do we need human beings anymore? They’re just slowing us down. It’s just extra weight, let’s get rid of them.” But the car takes on the personality of the last person who drove it. Whoa. There you go.

In other words, imagine the Judgment Day War from The Terminator, if Arnold Schwarzenegger looked like a cute red race car.

The Cars taking on the personalities of the last person that drove them is interesting, too. That would explain why some of the vehicles talk like (and are even named after) famous racers like Mario Andretti and celebrities like Jay Leno. It’s somewhat comforting to know that when the cars gain sentience and murder me and everyone I love, my Toyota will adopt my personality and that something in the post-human wasteland will still be eating movie tie-in menus (“I’ll have one of everything on McQueen’s Cars 3 drive-thru menu please”) and watching Gymkata (or as it would surely be called in Cars world, Gymkhana).

As for the other rules of Cars, Ward told me a couple, though he acknowledged that some of them are occasionally broken. Number one on the list: “You’ll never see the doors open,” Ward said. “Because the brain and the eyes are in there, we don’t want anything falling out of the side.”

Pixar

Ward also revealed that at one point Cars 3 was going to finally explain how Paul Newman’s character, a former racer named Doc Hudson, died. The character was retired after Newman passed away in 2008. Doc dies offscreen between Cars and Cars 2, but aside from an acknowledgement at the beginning of the sequel, there were no details about what exactly happened to him. “I don’t think we paid it enough [attention],” Ward told me.

In an early draft of Cars 3, viewers would have seen a flashback to Doc’s death. Ward described it as “a really tender moment where McQueen’s driving and Doc’s following him and it’s like the day your mentor passes away.” Eventually, the filmmakers decided the scene was “just depressing” and cut it from the finished film. You will see Doc Hudson in Cars 3, though, in flashbacks. Pixar went into its archives and found unused audio recordings of Newman from the first Cars. “Every line you hear in this film is Paul Newman,” Ward noted.

Don’t expect to hear about how Doc got Paul Newman’s voice, though, even if by Ward’s logic that would mean he was actually owned by Newman before the actor’s death. (Newman was a racing enthusiast and car collector, so it’s plausible.) When I kept pressing, Ward did offer me one other possible explanation for the world of Cars.

“[Cars 3 production designer] Jay Shuster did a great drawing a long time ago of a meteor hitting the earth,” Ward said, then mimicking a “Poof!” sound effect. “And all the humans are gone and all of a sudden the cars start rising up and moving around.” Just something cheerful to consider the next time you’re watching these charming kids’ films. Cars 3 opens in theaters on June 16.