Originally Posted by banerjek

20mph is not possible in the city.

For over a decade I had over a 40 mile RT commute. When I was at my peak, a 20mph RT average on one of my fast bikes was a disappointment though I had to work hard for it. However, that ride also had a 19 mile stretch with no stoplights, signs, or turns to slow me down and it was pretty flat.

I live in Portland now. Even if I'm only going a couple miles and it's downhill, I never get anywhere near 20 -- I'm lucky to break 16. It's just not possible with all the turns, signs, etc.