The cash-for-clunkers policy seems based on the mistaken view that the number of miles traveled is independent of the price or pleasure of driving. I call this the “lump of travel fallacy,’’ which is one of a family of lumpy errors that all assume things will stay fixed when they won’t. The lump of travel fallacy misleads leaders into thinking that billions spent on highways will eliminate congestion. Yet economists Gilles Duranton and Matthew Turner have compelling evidence that shows car travel increases essentially one-for-one with the amount of roads.
Glaeser, Edward L. "Program has Clunky Reasoning." Boston Globe, August 8, 2009.