The next time you take a trip within the U.S., I encourage you to try a thought experiment: Imagine how long the same trip might have taken a half-century ago. Chances are, it would have taken less time than it does today. The scheduled flight time between Los Angeles and New York, for example, has become about 30 minutes longer. Aviation technology has not advanced in ways that speed the trip, and the skies have become so crowded that pilots reroute planes to avoid traffic. Nearly every other part of the trip also lasts longer than it would have a few decades ago, thanks to traffic on the roads and airport security. All told, a cross-country trip could take a few more hours today than it would have in the 1970s. Shorter trips also take more time. Auto traffic in almost every metro area has worsened, and the country has done little to improve its rail network. In 1969, Metroliner trains made two-and-a-half-hour, nonstop trips between Washington and New York. Today, there are no nonstop trains on that route, and the fastest trip, on Acela trains, takes about 20 minutes longer than the Metroliner once did. The speed at which