I don't mean this in a competitive way. I know I ride slower than racers or even scenic riders, because some of them have passed me, but I suspect I ride a bit slower than some of you, too. On the other hand, I see a guy going the other way many mornings at what must be about 10 MPH, so I'm wondering how wide the range is. In good weather, I can average between 14-15, but more often it's 13 something, 12 something in bad weather. I suppose it also depends a lot on your ratio of stoplights to open stretches. I have about 1 red light or stop sign per mile (averaging it out).
I wonder what else influences speed. I have a hybrid, and I know that the upright position generally gives less power than leaning over. No pedal clips. And I wear everyday clothes, not biking duds, so I guess I'm not as streamlined.
There's one downhill on my route where I have gotten up to 30 for a few glorious seconds. Of course going up the same hill the other way slows me down to 8 sometimes!