US Highway 191 was renamed after some fanatics thought that the old Route Number was, "evil" . It was US Highway 666, also referred to as The Devil's Highway, Highway To Hell, and the Devils Rope. The easiest way to attract tourists and traffic is to call it Coronado Trail, since it actually closely follows the trail blazed by Coronado in his search for Cibola and the 7 Cities Of Gold. Now you know.
Devil' Rope was a term used in the 60s because like a rope, it winds and twists. A little more research and you will see the term. Either way, the name sounds cool, and it truly is ONE HELL OF A RIDE!