I picked up a riding partner on my way home from work this evening. This guy and I turned onto a street at the same time. He was ahead for a couple miles, then I caught up and he was happy to give me a draft. We swapped places after 3 or 4 miles, swapped again after another 3, then I turned off after 2 more miles. We were doing 21 mph on the flats. Average for the 13 mile commute was 17.0 mph. Hope I run into him again as it gave me a nice speed boost.