An automobile, sometimes called a motor car, is a wheeled passenger vehicle with its own motor. It is used mostly on roads for transportation of people rather than goods, and can seat one to seven people. It has a steering wheel, pedals for operating the brakes and controlling the speed (and, in a manual transmission car, a clutch pedal), a gear shift lever or stick, and a number of buttons and dials. Modern cars have become more complex with the introduction of systems such as air conditioning, and some have replaced physical controls with secondary controls for things like in-car entertainment and navigation.
Despite their convenience, automobiles have brought with them new problems such as road congestion and environmental damage. The main problem is that most automobiles use gasoline, which releases carbon dioxide and other harmful gases into the atmosphere when it burns. This problem has led to concerns about global warming, although new types of fuel and catalytic converters have reduced the impact.
Automobiles have also led to suburbanization, in which families moved away from city centers and built houses surrounded by lawns. In the United States this trend was encouraged by government programs that subsidized the construction of new highways and paved urban streets, along with zoning laws that allowed for building huge tracts of land devoted to single-family homes.
Until the 1920s automobiles were rare, with most people traveling by foot or horse. The introduction of the automobile revolutionized many aspects of life in the United States, and worldwide. It enabled people to commute to work in cities and towns, travel to distant vacation spots, and shop at stores that were previously only accessible by foot or horse. It also created a wide range of jobs in the retail, service, and repair sectors.
The inventor of the first modern automobile, Henry Ford, introduced industrial manufacturing methods to automobile production. His assembly line, in which workers stay in place and perform only one task at a time, made it possible to produce large numbers of cars inexpensively. As a result, the automobile became more affordable for middle-class Americans. It was this development that, more than any other single factor, made it possible for the United States to dominate the world economy in the 20th century.
Automobiles can be very dangerous if driven poorly or in reckless fashion, as is often the case with young drivers. Accidents can also be caused by mechanical failures, such as a broken axle or ruptured tire. Other dangers include collisions with large animals or other vehicles, and the tendency of some drivers to get distracted by phone calls or music players in their car. Some automobiles are prone to rollover accidents, in which the vehicle rolls over or becomes unstable. For these reasons, it is important to follow traffic laws and keep your vehicle in good condition. Cars are also expensive to own and maintain, and it is important to weigh these costs against the benefits of having a car.