"The usual suspects on the comment board are, inevitably, arguing that rail transit should pay for itself. The obvious response is that road transit doesn’t; why should only public transit have to self-finance, when private vehicles generally drive on free roads built and maintained out of taxes?
But in a way that misses the larger point: urban transportation is an area in which we know that market prices bear very little relationship to true social costs. Even if you ignore environmental impacts and the national security implications of oil imports, the fact is that driving in an urban area, especially in rush hour, imposes huge congestion externalities on other people."
Perhaps the definitive article on the separated cycling lane on Hornby..