Automobiles are four-wheeled vehicles with internal combustion engines that run on gasoline or another liquid fuel. They are designed to travel primarily on roads and to carry people rather than goods. There are many different definitions of what constitutes an automobile, but most specify that it must be powered by a piston-type internal-combustion engine and have at least two wheels in contact with the road. The engines may be water-cooled or air-cooled, but they are generally positioned in the front of the vehicle, with power transmitted to the rear wheels or to all of them. Some vehicles are powered by electric motors alone, or in combination with a traditional gasoline engine.

Modern life would be inconceivable or at least highly inconvenient without automobiles. They can carry more people than buses, trains or bicycles, and they can reach places not easily accessible by other forms of public transportation. They also provide a great deal of convenience in that they can be driven at one’s own pace and allow people to avoid having to depend on others for rides.

Automobiles were first invented and perfected in Europe in the late 1800s, but Americans came to dominate car production in the first half of the twentieth century. Henry Ford innovated mass-production techniques, allowing his Model T to be produced at a price that made it affordable to middle-class families. Ford, General Motors and Chrysler emerged as the Big Three auto manufacturers, with a total production capacity that dwarfed the combined output of all European makers.

American consumers quickly embraced the automobile. It became a symbol of modernity, and its demand stimulated a host of ancillary industries. Steel and petroleum companies benefited from the industry’s tremendous sales, while other manufacturers such as rubber, glass, and tinware saw their markets expand dramatically. In addition, the massive population of the United States and its vast expanse created a huge market for this new form of transport.

Consumers quickly grew to love the freedom that the automobile brought them. Families could explore pristine landscapes and shop in towns and cities. Teenagers enjoyed the independence that driving afforded them, and dating couples found it easier to spend time together in a private space.

The automobile’s social effects were as significant as its technological advances. It encouraged family vacations to previously inaccessible countryside, and it allowed urban dwellers to rediscover pristine cityscapes. It was a source of romance, and it helped to foster relaxed sexual attitudes. The automobile brought problems as well, however. Traffic congestion and accidents increased, triggering demands for licensing and safety regulations.

The automobile has been a key force in change throughout the twentieth century, and its role will likely continue to be important into the twenty-first century. It continues to be a major industry, providing tens of thousands of jobs, and it is the main customer for many other industrial products such as steel and petroleum. In addition, it is a major source of pollution and a drain on the world’s dwindling oil supplies.