Automobiles (also known as cars, or ) are four-wheeled motor vehicles for carrying people that use an internal combustion engine to make them move. These engines burn fuel, usually gasoline or diesel, to create power that drives the wheels and electric energy for lights and other systems in the car.
The automotive industry is the world’s largest and most important manufacturing sector. It generates millions of jobs in factories that make automobiles and at dealerships that sell them. It also supports many other industries that provide supplies and services for the automobile, including rubber and plastics, oil and gasoline and restaurants and motels that serve drivers and passengers.
Most of the world’s automobiles are powered by an internal combustion engine that uses gasoline or diesel fuel to run. The engines turn a crankshaft that drives a transmission, which changes gears to control the speed and direction of the wheels. The power from the crankshaft also drives a generator that produces electricity to operate car lights, radios and other systems. The automobile’s other major systems include braking, steering and suspension.
Until the late 19th century, most automobiles were built by hand by individuals who made them to order for wealthy clients. The invention of the automobile assembly line by industrialist Henry Ford changed all that. Ford’s technique allowed him to produce a single model of automobile in large numbers at low cost, making them available to more middle-class buyers.
In addition to allowing people more freedom of movement, the automobile stimulated leisure activities and created many new businesses related to them, such as roadside recreation and dining. It also encouraged the development of cities and suburbs with urban amenities. Road construction became a significant item of government spending, reaching a peak with the Interstate Highway Act of 1956.
Although cars have given people a lot of freedom and convenience, they have also caused problems. Millions of people die in automobile accidents each year. Their production and operation create pollutants that damage the environment. They also eat up valuable parking space in cities and cause traffic congestion. And, of course, the emissions of fossil fuels by automobiles contribute to global warming. However, most of the harm done by cars is beyond the control of individual consumers. Only by using a combination of fuel-efficient, low-emission cars and walking or cycling for short trips can the environmental impact of the automobile be reduced.