Semi Trailer Slips Over Edge of Icy Mountain Road and Plunges Down Slope Colorado Rockies — A routine winter drive through a narrow mountain pass turned into a terrifying scene when a semi truck lost traction on an icy curve, sending its trailer sliding off the roadway and over the edge of a steep drop. Dashcam footage shows the tractor-trailer creeping along the snow-dusted road carved into a sheer rock wall. As the truck rounds the bend, the trailer begins drifting toward the shoulder, its whe