Some of these responses are something. Either we have a very talented group here or people are oblivious to their real speed. If you look at the logs of some of the pro's at various sites, you'll get a sense of what their training is. T. Hamilton last year did 13,000 miles at an average pace of 18 mph.

Many clubs post average riding speed for various fitness levels/distances. These range from AA (typically what clubs call their top category) that average 20 to 22 mph, A at 19 - 21, BB 18 - 19, B 16-18, down to D at 13 - 14 mph.

People that do long races put in lots of miles at the 18 to 20 mph pace for endurance, where the 18 end is usually on hilly courses. Then they do speed workouts to go faster in race conditions.