Automobiles are four-wheeled, motorized vehicles used for passenger transportation and powered by an internal combustion engine using a volatile fuel. A modern automobile consists of thousands of components with specific design functions and is often a complex technical system. These include the body, chassis, and drive systems; engine; transmission; electrical, control and safety systems; and fuel and exhaust-control systems. Some of these systems have evolved from breakthroughs in existing technology, while others were influenced by new technologies such as electronic computers and high-strength plastics or by environmental factors such as air pollution and safety legislation.
The scientific and technological building blocks of the automobile go back several centuries. The first steam- and electric-powered vehicles appeared in the late 1700s and 1800s. The gasoline-powered automobile, however, proved to be the most successful. The development of mass-production techniques by American automakers such as Henry Ford and his rivals allowed these vehicles to become affordable for middle-class families.
The automobile brought with it changes to the way people lived and worked. People gained access to jobs and places to live, and leisure activities expanded to include travel, entertainment and restaurant and fast food services. But it also brought harm to the environment in the form of air pollution and a drain on dwindling world oil supplies. Postwar, the era of the annually restyled road cruiser began to decline as questions were raised about nonfunctional styling at the expense of safety and quality; government requirements for seat belts and highway rules; and increased pollution, energy consumption and the draining of world oil reserves.