Introduction Thousands of years separate the invention of the wheel and the first self-propelled vehicle. The intervening centuries witnessed wind-powered vehicles (Figure 1)@ wheeled sailing ships@ and muscle-driven vehicles (Figure 2)@ in which human or animal power@ hidden or in plain sight@ served as motive power. However@ these did not represent real progress@ because neither wind nor muscle power was faster@ more powerful@ or blessed with greater endurance than the combination of horse and wagon. In other words@ development of self-propelled road vehicles depended on finding a suitable power source. The availability of this power source around 1885@ in the form of a lightweight combustion engine@ resulted in a paradigm shift 50 years after the railway had revolutionized transportation. Suddenly@ it was possible to equip not only two-wheeled vehicles@ coaches@ and trucks@ but also ships and boats@ streetcars@ airships@ airplanes@ fire engines@ and many other devices with an engine that@ thanks to liquid fuel carried on board@ could operate anywhere. Motorized road transport quickly overcame the decades-old advantage of the railroad@ and set new standards for free-ranging surface transportation@ time savings@ and individual mobility. In the process@ mass motorization has spawned problems of its own which threaten to grow to uncontrollable proportions: energy consumption@ dwindling resources@ environmental pollution@ climate changes@ and traffic accidents@ to name just a few. The automobile must be regarded not only from technological or economic standpoints@ but also from an ecological perspective.