Abstract
In a world so transformed by the automobile that whole landscapes and lifestyles bear its imprint, a significant fact goes unnoticed. While societies the world over define transportation in terms of engine power, the greatest share of personal transport needs is met by human power. In some developing countries pedal power is an important part of national economics and the only alternative to walking that many people can afford. In industrial countries the use of bicycles should en encouraged to prevent traffic congestions and air pollution.