How do you tell which ones are commuters?

I don't know whether I should count everyone who's not wearing lycra or only those wearing high-vis vests, helmets with mirrors, and riding a practical commuting machine. Simply only counting those wearing high-vis vests would eliminate everybody I see on the road excluding the hordes that come to town once a year for a century ride who all seem to have high-vis vests and helmet mirrors. High-vis, mirrors, and helmets for that matter are very uncommon sights here.

But seriously. How do you know who's commuting?