The south and the west may be winning the demographic race, but America's economic winners are the places that have improved their productivity--something which doesn't turn on the sheer numbers of workers they have on tap, but rather on how skilled and innovative they are.
But the lesson is clear. Highway construction generated some positive effects and some negative effects. We tend to focus on the positive effects and remark on how constrained the economy might have been without a highway boom. But absent a highway boomwould have been built and markets would have optimised to that something. It's not clear that the savings from highways are so substantial that the American economy is clearly better off as a result of the system's construction. Highways obviously had a large effect as an idea, and they made direct contributions to the economy as a construction enterprise, but the net addition to growth through trade is uncertain, and probably much smaller than most people assume.
That doesn't mean that infrastructure isn't worth building. New infrastructure will quite often yield real cost reductions, and my assessment is that many new projects, particularly those along corridors that are already busy and congested, would probably produce benefits. I suspect that the potential benefits would be clearer if roadways were kept free of congestion via tolls; toll revenues along some well-traveled routes would meet or exceed the cost of construction of new infrastructure capacity.
The results have in general not been impressive. As Jeff Wood catalogued last week on The Overhead Wire, these investments have yielded very limited ridership — especially on a per-mile basis. Nevertheless, cities continue to make plans to focus their spending on them: Kansas City announced in 2009 that it was considering a 150-mile commuter network; late last year, Indianapolis suggested its primary rail investment would be in a commuter line to its northeast suburbs.
Except in the older cities (which have legacy commuter rail systems for the most part), the downtown job base has been falling off as a percentage of the metropolitan area’s total employment for decades. The rise of non-traditional working patterns that rely on Third Places and home offices mean fewer people need to get into central business districts for the same amount of work to be done. In most places, the center city simply isn’t a big enough attraction to require shuttling people to it from distant locales via big, heavy diesel trains running a few times a day. Indeed, in many cities, that work could probably be better done with a few express buses.