Bad planning simply extrapolates past trends: “We experienced 2% annual growth during the last decade, so we’ll assume that will continue into the future.” Good planning attempts to understand underlying factors that affect change. Such is the case with the price elasticity of vehicle travel, that is, the changes in vehicle travel caused by a change in transport prices (fuel, parking, tolls, insurance, etc.).
Automobile travel imposes significant health risks. Traffic fatality rates, obesity and related illnesses such as diabetes, and total air pollution emissions tend to increase with per capita annual vehicle mileage. These risks help explain why United States residents have significantly shorter life spans than peer countries: average longevity is almost 1.5 years below the OECD average, despite spending about 2.5 times as much per capita on healthcare.
On Earth Day the US Department of Transportation released an important new, 605-page report, Transportation's Role in Reducing U.S.