I mentioned these a few days ago, but my favorite part of Mario Kart games these days is the in-universe ads for various Mario-themed automotive products. Whatever world these games are set in, it obviously doesn’t have to worry about global warming, because not only are there plenty of vehicular support companies there, but they’re all either themed or named after some aspect of Marioness. We’re not told literally anything about these companies other than what we can glean their promotional imagery plastered all over the place, but I presume that the Mario characters aren’t just spokespeople/things, but actually own and run them.
In Mario Kart 8, Super Bell Subway was an extravaganza of environmental world building, implying far more about the Mushroom Kingdom than we ever hoped to get, and Mario Kart World is like an extended version of that. As with most Mario games, the only elements that will carry over between games are the ones Nintendo thinks are sufficiently marketable, and even then they’re known to throw out characters that fall out of favor (R.I.P. Toadsworth). But we might consider these glimpses as one version of what every day life in the Super Mario World might be like.
Check out the Mario Wiki page for Mario Kart 8 Deluxe: Super Bell Subway, which has a complete list of the signage used in that track. It also mentions that most of that game’s tracks are mentioned on the route maps in that course, as if you could hop a train and go there. Maybe it gave Nintendo’s designers the idea to make Mario Kart World a single cohesive map?
Anyway, here’s some more track signage from this heavily car-dependent version of the Mushroom Kingdom.












And, unrelated, under characters there’s this person:

Um, who in the name of the Question Block of Doom is that supposed to be?