Several years back , I was "that guy". 1-ton dually 4x4 with 2-place enclosed. Studs on the front, chains on the rear. 1/2" of frozen rain on the road. Almost to the top when I started going backwards. The whole setup did a gradual turn to the left. I ended up with my front wheels of the downhill side and my trailer was in the ditch on the left hand side. So, I unhooked from the trailer, had several guys pushing on the front end so I was pointed uphill. Drove all the way to the top, turned around, drove down to the trailer and hooked back up, drove it to the bottom, turned around and made it to the snowpark in one piece. The road was just wet at the bottom but it was frozen at the top, but just looked wet. It was so slick up there you couldn't stand up on it for nothin'. Only blocked about 8-10 vehicles for about a half hour. I would rather not repeat that journey, wasn't much fun looking at my front tires off the asphalt on a cliff. I thought I was going over for sure.