hardees/ carls jr

i was just lookin at the chineese minitrucker thread n he was standing next to a carls jr. trashcan it reminded me of my trip out west.. i was just wondering why the east side of the U.S. is called Hardees and west is all known as Carls Jr's?? i was pretty confused and agrivated i couldnt find a hardees to get come cinnamon raison biscuits!