Low 30sF, and fast, with a light headwind. Something was shadowing me. I was doing 20MPH for a while and it wasn't dropping back. Very unusual. I was dressed for the temperature, and after about 2 miles of fast cruise, I started to overheat. Eventually I pulled over to take off my gloves and unzip my jacket. The shadow went by. Turned out to be a roadie in full lycra with a messenger bag. (Compare & contrast with my 35 pound dualie MTB with fat all terrain tires) I then shadowed him until we went different ways. He was fast. Possibly the fastest rider I've ever encountered on the MUP here.