Public Transport has two primary goals, which actually compete with each other rather than complement each other - Patronage and Coverage. This distinction between the two functions matters a lot for how public transport networks are designed, and which projects are worthy of funding - but it's a distinction that's rarely made explicit. So you'll often have one group of people arguing for a project on the basis of Coverage and the other against it on the basis of Patronage - neither side is really speaking the same language, so the debate goes nowhere.
