@Leaniv if you visit those buildings in pillars at night you can VERY occasionally see some flickering lights from some of the windows. I also swear I saw some spinning fans on the ACs but that might have been just a glitchy texture. So I think there might be someone living there.

There's also some speculation that the "fumes" themselves are what drive the cars. For one, when you "die" in game, it seems that your "spirit" is transferred to another car. When you're missing a car door or hatch, there's just black nothingness in there, no seats or anything... until you hit turbo, and then you can see some purple/blue streaks glow inside your car.

I don't think this is an entirely supernatural setting though, because for one, there are harvesters and things to upgrade your car, and also... outhouses. Unless cursed car ghosts also need to go to the bathroom, I'm sure some kind of people live in the universe of Fumes.

Looks like those roots are seeking the "Fumes",the gas that is inside the vehicles and also in the sky. There's also a solid form of Fumes:you can find those inside the escort trucks for the defence/attack convoy missions,with roots around it. So far is unknown where all of this comes from.The description of a weapon in the game implies that Fumes are also a "resource" used in manufacturing,most likely of weapons,thats why there are moving factories: if they are stationary for a short time,the roots will grow towards it. The scrapper is also aware of this,since will say "lets move before it happens" if you ask them to stop. Seems that those huge building appartments were also aware of this,since they are built on huge pillas that keep the houses far away from the ground (even if looks like there are no life inside those buildings)

this might blow your mind but if you turn off your engine (i key if you havent changed it) then the vines wont show up when you come to a halt

I originally thought those ramp things were like, the blocked air vents for abandoned fallout shelters, but seeing that they work to stop death by vine I wonder if they were specifically built so you could stop your car on it (to repair and reload if you don't have a truck to do it in?)