Automobiles are road vehicles that use a gasoline, diesel or other fuel to power internal combustion engines. The engine propels the wheels by pushing down on a piston that is energized by the explosion of the fuel in the cylinder. The resulting energy turns the crankshaft and drives the rear or front wheels. A car’s drive train can also be powered by electric motors that run off an alternating current. Some automobiles have air-cooled engines instead of water-cooled ones, but the former are still in use for some types of commercial trucks and buses.
The automobile has been one of the most important forces for change in twentieth-century America. It has become a central part of a new consumer-oriented society and a major source of employment in ancillary industries such as steel and petroleum. It has been a symbol of freedom, and for many Americans it has symbolized their own personal wealth.
Although the technology for an automobile existed by the late 1800s, it took Henry Ford to make them affordable and practical. His revolutionary assembly line production method greatly reduced the cost of automobile manufacturing and allowed Ford to quickly outpace competitors. The Ford Model T was the first automobile to combine state-of-the-art design with moderate price.
By the end of World War II, 88 percent of American households owned a family automobile and it was the most common form of transportation. The car brought with it changes in lifestyle, social attitudes and public policy. It encouraged family vacations and allowed urban dwellers to rediscover pristine countryside. It helped teenagers gain independence and facilitated relaxed sexual attitudes. It led to the proliferation of new services such as motels, hotels and fast food joints. It also caused harm to the environment by creating pollution, and it required government regulation such as highway rules and driver’s licenses.
The automotive industry has grown to be the world’s largest producer and user of oil, a nonrenewable resource. The industry has made significant contributions to the economic, technological and cultural development of the nation and other nations, and has helped to shape the worldwide economy. The automobile is a symbol of the promise and the perils of modern society.
There are approximately 1.4 billion cars in operation throughout the world, and about three trillion miles (5 trillion kilometres) are driven each year. There are about 3 million deaths related to driving accidents, and a great deal of traffic congestion. Despite its many problems, the automobile remains an indispensable part of our daily lives. Almost every city in the developed world has a street network with access to automobiles. Some streets are exclusive to pedestrians, but the majority of streets have space for vehicles, including public and private transit systems. Most public transit systems in the developed world have trains and trams, but the most common means of transportation is the passenger car. It is used by people to travel to work, shopping, leisure activities and visiting friends and relatives.