I suspect 80 is probably on or beyond the high end of the normal range for commuters - and we are talking about commuting here. As for me, I've never timed my cadence - for me the bike is a transportation tool that I pedal as hard and as fast as feels comfortable. It's never been something I try to squeeze every last drop of efficiency out of. Heck, I've never even owned any kind of cycling computer, so I have no idea how fast I go. As long as the bike gets me where I want to go faster than running, I'm happy.