There’s no denying that the modification which changes ATS the most is the map. If you can add more states, regions and roads for exploration, the game becomes more interesting. SCS Software does a tremendous job bringing US countryside and cityscapes into the game. You have the better part of Western United States projected into the game with meticulous detail. However, the mod community take it a step further. You can find more detailed variations of individual state maps which are usually called state expansions. They add more towns, cities and roads as well as picturesque countryside to the game.