Automobiles are land vehicles designed to carry people and used for passenger transportation. They are usually propelled by an internal combustion engine that uses a volatile fuel such as gasoline. Automobiles are now an essential part of life in many countries. They make it possible to avoid relying on others for rides and allow individuals to control their schedules without being bound by the hours of buses or trains. However, the automobile can also lead to traffic congestion and air pollution, and it can cause injuries when it crashes.

The modern automobile was first perfected in Europe during the late nineteenth century by inventors such as Gottlieb Daimler and Karl Benz. By the early 1920s it had become a major force for change in twentieth-century society. It was the backbone of a new consumer goods-oriented economy and one of its chief consumers of steel and petroleum. It spawned industries that produced such vital consumer goods as tires and oil-based plastics, and it revolutionized the manufacturing methods of these and other related industries.

America’s large geographic area and a highly diverse population created the potential for great demand for automotive transportation. Cheap raw materials and a tradition of industrial manufacturing encouraged the development of a large number of firms that could produce cars at competitive prices. The first American companies succeeded in reconciling state-of-the-art design with moderate cost by developing innovative production methods. Henry Ford’s use of the assembly line greatly improved the speed and quality of automobile production, making it affordable for middle-class families.

Cars are available in a wide variety of shapes and sizes to suit individual tastes and purposes. The most common types are sedans, which have four doors and can hold five or more passengers. Coupes are similar but have two doors and are more sporty looking. Station wagons and vans are larger and made for hauling cargo or more passengers.

The safety of automobiles depends on the way in which they are constructed, operated, and maintained. Crash tests are conducted to evaluate the crashworthiness of cars, while road test procedures can measure driving characteristics such as stability, handling, and braking. An accident can also result from driver error, such as indifference to the speed limit or intoxication.

The era of annually restyled automobiles began to wane in the United States during the 1930s as consumer expectations and government regulations began to have an impact on automotive form. The advent of seat belts and highway safety requirements, limits on gas consumption, and emissions standards set the stage for a new era of functionally designed, functionally efficient cars. In the United States, it is now impossible to imagine daily life without access to a personal vehicle. In other parts of the world, auto-dependence is less prevalent. But the automobile is still an important mode of transport, and other forces-the electronic media, the laser, the computer-are transforming our lives as the Age of the Automobile melds into an Age of Electronics.