THE WASTELANDS
The Wastelands, to sum it up, are the miles of land that are between / around built cities. The terrain varies but you'll find open, tundra, oasis, steppe, desert, swamp, forest, marsh, river, and hill. Because of radiation from the nuclear war, a lot of animals / species have mutated or died. This also includes plant life. The land is very unhabitable and it's very hard to get use out of it since the soil lacks the nutrients for things to grow. It's basically a dead, barren place. Wasteland inhabitants are known to be violent and dangerous, that's why you won't find anyone traveling through it. The System provides bullet trains across tall bridges that are protected by the military for those who wish to travel to certain cities. There is also the choice of air travel, which is preferred among those whose destinations cannot be accessed by train (Every city has a limited amount of bridges connecting them to other cities, usually, if you'd like to go to a specific city, you'd have to take several trains to get there). You're also able to use these bridges yourself (driving through it by car), but there will be checkpoints, much like those in a city, to ensure your safety. Of course, you can always risk it and travel through the Wastelands, since everything is connected through it.