Yes, people inflate their numbers by various means, because of egos. I'm sure men do that more than others. So they take the bigger number, which is their typical cruising speed (TCS), not moving average (MA) or end-to-end average (EEA). However TCS is actually a useful number, among other numbers. To gauge if two riders are compatible, it could be useful to compare all three: TCS, MA, and EEA. I don't mind stopping a lot, so my EEA is very low, which could annoy people.

As for how fast the average person goes, it's very variable. Consider, also, that people who pay attention to these statistics are, by definition, bike nuts, so the cited numbers are going to be far above average of the spectrum of bike riders. I meet some people who say, "I love to ride my bike!" and it turns out they take three outings per summer on a pedestrian path in a park. They go one to five miles at an 8 mph pace.

And there are people who commute on crappy old bikes. If you average them into the entire population, most people on BF are speed demons.

Neither the 8 mph park cyclist nor the commuter on the crappy old bike knows how fast he goes.

And the amount of power required to increase your speed by 1 mph is quite a lot. So there are so many levels of cyclists, and it's so difficult to keep up with someone just two or three levels above you. So the answer is quite elusive.

Now if you want to compare bike nuts like us, I'd say the range is 12 to 19 mph. Even that is a huge range. And when you mix in my wife, she can't manage to improve her moving average above 10 mph! And that's not from lack of trying. Mind you, we live in a hilly area.