Automobiles are the principal means of transportation in industrialized societies. They account for more than three trillion miles (five billion kilometres) of travel annually, and their manufacture accounts for large percentages of the world’s gross domestic product and employment. During the twentieth century automobiles have undergone numerous changes. These include federal standards for automotive safety, pollution control, energy consumption and vehicle design. They have also changed the way people live, work and play by allowing individuals to travel long distances with ease. This has led to the growth of a wide range of services, including restaurants and retail stores that cater to the needs of car passengers.
The automobile revolutionized many aspects of life in the United States and around the world. It provided a new level of personal freedom that has allowed people to visit distant cities, work in different places or even change careers. It stimulated a number of industries, especially those that produce fuel, rubber and plastics, and it created new jobs by requiring workers to build the vehicles and supply them with parts and gasoline. The automobile also made it easier for families to spend time together and enabled women to enter the workforce and participate in public life.
Until the invention of the automobile, human beings had to carry all of their possessions with them wherever they went. Some early vehicles were steam-driven, but these had to be manually operated and were impractical for use over extended periods of time. Others were powered by electricity, but such machines were not very fast and had to be recharged frequently. The earliest modern motorcars were developed in Germany and France toward the end of the nineteenth century by such men as Gottlieb Daimler, Karl Benz, Emile Levassor and Nicolaus Otto. Their 1901 Mercedes model was considered to be the first truly modern motorcar in all respects. Its thirty-five horsepower engine weighed only fourteen pounds per horse and achieved a top speed of fifty-three miles an hour. Its moderate price and low operating costs put it within the reach of middle-class Americans.
The basic components of a motorcar are its chassis, wheels and transmission. The body is a metal frame that supports the internal workings and provides a framework for a roof, windscreen and doors. Its interior consists of seats for the driver and passengers, and a dashboard that displays instruments, such as the speedometer, gas gauge and odometer. The exterior of the vehicle is shaped to provide an attractive and aerodynamic appearance. Its exterior also includes windows that allow the driver and passengers to see where they are going. The windows are typically framed with glass that reduces noise and light pollution. The windshield and other windows can be tinted to reduce the amount of sunlight that enters the car. This helps to keep the inside comfortable and cool. The vehicle’s interior also features an audio system to allow passengers to listen to music and news broadcasts.