A fairly quick doodle to give a basic idea of how the Oasis work on the world of Oktahv ("ock-tuh-haw", meaning "dirt, dust, sand, loose debris"). The planet itself has one large continent that wraps around the middle of the planet, with a little more in the upper hemisphere. North and south of this are the oceans. Roughly 30,000 years ago, aliens of known origins and species happened upon this world. At the time, it was mostly desert, with 17 large Oasis and frequent, extremely violent sandstorms. It had life, but not sentient life. These aliens set up a weather control device somewhere underground, set it to alter the weather to make the planet a more tropical paradise, and then left. Around 10,000 years ago, other sentient species discovered the planet, naming it "Lane" ("Luh-neh", meaning "Green"), and building it into at first a vacation resort, and later allowing for permanent habitation. All was going fairly well until around 100 years ago, when the weather control device exploded, causing Lane to revert back to Oktahv. Civilization didn't exactly collapse, but it did falter and crumble a bit as the sands reclaimed most of the landmass. People found and claimed each of the 17 oasis. Each roughly covering an area the size of Texas, the Oasis first became their own mini-nations. While each Oasis was capable of supporting large populations, each of them also contains certain natural resources that others lack.
13 of the Oasis formed a strong alliance. 3 of the others allied with eachother, and drew up a loose peace treaty and trade agreement with the main 13. The final Oasis rejected both groups. The alliance of 13 became known as the Settlers, who work to rebuild the world and civilization along with it. The alliance of 3 became the Scavengers, who seek out pieces of the old world, in hopes of helping to learn forgotten history and perhaps finding some way to make Oktahv become Lane once again. The remaining Oasis became the Raiders, who take what they want if they can. Though rougher around the edges and more prone to resemble your more typical wasteland raider aesthetic tropes, the majority of the Raiders are really not stupid enough to openly oppose the larger groups. Not within the last 75 years, anyhow. Nowadays, the Raiders are usually less brutal and can be bargained with. Often, the Raiders are willing to leave other alliances alone in exchange for the occasional deliveries of supplies. There are, however, occasionally raids on smaller Scavenger groups, or the occasional greedy Raider party who might mess with a Scavenger or Settler convoy on the open roads or out in the wastelands. But such parties are often not long for the world, either by the hands of mercenaries like Buck, or well-armed transport drivers like Gearjammer, or the Raider leaders. For their part, the other alliances don't go out of their way to mess with or interact with the Raiders, and often have enough surplus that what the raiders ask for in supplies is an agreeable amount. Heavy 8-lane roads were built to connect the Settler and Scavenger Oasis, traversable by the big transport trucks and convoys. With the Raiders being as they are, a single offshoot of one of these big roads leads to the Raider Oasis. Perhaps most surprisingly, within the past 20 years, many Raiders have started maintaining not only their road, but the others that aren't too close to other Oasis.
The color coding on the image basically shows the zones of a typical Oasis. Blue = fresh water. Greens = farmable land. Brown = residential areas. Yellow = business areas. Orange and red orange are usually open areas, but may also contain factories and power plants, or be areas that are mined for minerals, etc. The red areas are the outskirts, where the defensive forces stay, and where the soil is becoming more desert-like. The black outline is the perimeter. Usually a big metal octagon wall around the whole Oasis to help keep out both Raiders and the sandstorms. The lines indicate heavy paved 8-lane roads. Unsurprisingly, there's not a lot of traffic lanes through the outskirts areas. Not pictured is all of the smaller roads and such, as that would make this look far too busy.