This chapter addresses one of the most persistent environmental and social problems in our society: the ecological effects of personal mobility. The dominant form of personal transportation is the car. As well as the obvious benefits of door-to-door transportation, freedom to move, satisfaction in driving and perceived social status, there are many disadvantages: local air pollution, mainly in cities; greenhouse gas emissions; road congestion; noise; accidents; use of space; and urban sprawl. On a personal level, many people are aware of the disadvantages but feel unable to act differently, especially as there are also many disadvantages to alternative forms of transportation (see, for example, Hardin 1968). Many people, however, also feel that the social effects of the car system are becoming unbearable. In the US the discussion of urban sprawl is often on the agenda (Gillham 2002). High levels of vehicle-related air pollution urged the state of California to develop its mandate for zero-emission vehicles (ZEV). Both in the US and in Europe local emissions are increasingly regulated (although until recently sports utility vehicles [SUVs] in the US escaped such regulatory control). Greenhouse gas emissions are high on the agenda, not only in Europe but also in many US states, municipalities and civil institutions.