'always reliable'? come on TriMet, even you know thats not true all the time...There are bus/max breakdowns, bad weather, emergencies, ect. that can all lead to late transit every once in a while.
Well, clearly people here in Portland do because the trains are all too often packed like a sardine can. But, if i remember correctly about something i read a while ago, more people ride the transit buses than light rail.