Paul Krugman, in his NYT blog "Conscience of a Liberal," apologizes for not writing more about the real cost of driving, and cites a new paper on the benefits of increased rail service, saying that it’s good work that backs up our intuition on the subject. He adds, “We know, as surely as we know anything in economics, that there are huge market failures here – that every time an individual chooses to drive during rush hour he or she is imposing huge costs on other drivers, on people who breathe the air, and more.”

The paper he cites is posted on Vox, a blog on “research-based policy analysis and commentary from leading economists." The paper’s conclusion: “In sum, recent empirical evidence on public-transport improvements confirms expectations of beneficial effects on road safety and environmental quality. Moreover, conservative back-of-the-envelope calculations that do not take reductions in congestion, noise and greenhouse gases into account suggest that public-transport improvements offer good value for money. Improvements in rail service frequency reduce external traffic costs worth as much as the costs associated with their implementation.”

Good reading from the economic POV: Krugman, and Vox.