Haulin is an older game. If you are playing on a modern PC, you might need to run the game in for Windows XP or 7 to ensure the mods render textures correctly without flickering. Search for "Busscar" and "Marcopolo"
Mods for "18 Wheels of Steel: Haulin'" can vary widely: Mods Bus Para 18 Wheels Of Steel Haulin Argentina Warez