I was in a quandry, my round trip is only 8 miles but I generally ride home for lunch which gives me two 8 mile round trips for a total of 16 miles. Sometimes there is a meeting, or my work team has a luncheon or training meeting & then I have to drive. Also when the weather gets really bad I sometimes drive to a 1/2 way spot & ride from there. I voted for 15 miles or less as a fair average. Don