Two Billion Cars: Transforming a Culture

While providing untold benefits, today's one billion motorized vehicles are contributing to worldwide problems with energy resources, climate change, and congestion. The number of vehicles is expected to reach two billion by 2020. In tracing out the complexity of problems and solutions, the authors call on the transportation community to summon its ingenuity to improve vehicles and fuels, introduce new mobility, and develop ways to alter travel behaviors.