Automobiles, also known as cars or motorcars, are wheeled, four-wheeled road vehicles designed primarily to carry people. They are propelled by an internal combustion engine powered by a volatile fuel. The modern automobile has evolved into a complex technical system of interrelated subsystems, each with specific design functions. These have resulted from breakthroughs in materials and technology such as electronic computers, high-strength steels, and advanced alloys of nonferrous metals.

The automobile was a powerful force for change in twentieth-century America. It became the backbone of a new consumer goods-oriented society, the lifeblood of petroleum and one of the chief customers for other industrial products such as steel and fabricated metals. It is a major employer and provides a large share of personal income for middle-class Americans. It is one of the nation’s largest industries and a key component in the world economy.

Modern life is virtually inconceivable without a car. The automobile has become the primary mode of transportation for nearly all households. The automobile has given many Americans a freedom and mobility they had never enjoyed before. They can travel to work and school on their own schedules rather than waiting for the bus or relying on the whims of friends. They can take weekend trips to places that were inaccessible or difficult to reach by train or plane. They can shop, visit friends and family, and run errands.

In the 1860s, Siegfried Marcus, working in Vienna, Austria, built an automobile with a two-stroke, gasoline-fueled internal combustion engine. It was a crude vehicle with no seats, steering or brakes, but it proved the viability of the concept of an automobile. Karl Benz of Germany is credited with perfecting the automobile in the late 1880s, and American businessman and engineer Henry Ford introduced production techniques that made the Model T affordable to middle-class families.

With the advent of the automobile, a host of new businesses were established to provide services to support the industry. Gas stations, hotels, motels, restaurants and amusement parks grew rapidly. In addition, highways were constructed and expanded to connect cities with towns, rural areas, and the countryside.

The automobile has brought new problems as well. It has contributed to air pollution and the destruction of natural habitats. It has also imposed a demand for new laws and government requirements such as seatbelts, safety features, driving licenses, and speed limits.