The automobile, often referred to simply as a car or auto, is one of the most significant inventions of the 20th century. It revolutionized the economy and society by connecting people in ways that had never before been possible. It is a symbol of freedom, power and wealth, and it has become an integral part of American culture.
The word automobile derives from the Latin “ad vehiculum” meaning “to carry in a vehicle.” In modern usage, the term refers to any four-wheeled motor vehicle designed primarily for personal transportation and propelled by an internal combustion engine using a volatile fuel. Trucks, vans, buses and limousines are all considered automobiles as well, although they differ from passenger cars in that they typically seat fewer than eight passengers. An automobile must meet certain criteria to be categorized as such, including a maximum speed of 55 miles per hour, four wheels, a steering wheel and an engine capable of producing at least 20 horsepower (16 kilowatts).
Among the most important factors in determining how a car performs is its intended use. Automobiles that are used off-road, for example, must have simple systems and be rugged enough to endure extreme conditions. In contrast, those that will be driven on limited-access highways require more passenger comfort options, enhanced engine performance and optimized high-speed handling and stability.
A car’s handling characteristics are influenced by its weight distribution, the location and size of its engine, and its suspension. For example, a rear-engined car is more likely to understeer, which results in the rear of the vehicle sliding outward as the driver turns the wheel. In contrast, a front-engined vehicle may oversteer, which causes the vehicle to swing wide as it turns the wheel.
To maximize the efficiency of an automotive engine, it is generally preferred that its crankshaft be located at the front of the vehicle. This arrangement allows the vehicle’s center of gravity to be closer to the axle and therefore improve stability. However, the advent of aluminum engines and new manufacturing processes has made it possible to place the engine at the rear without necessarily compromising stability.
Today’s cars are designed with a variety of design principles in mind, from the look and feel of their interiors to the way they respond to driving dynamics. Some brands, such as Lexus and Honda, are known for their luxury and reliability; others, such as BMW, Porsche, and Subaru, are recognized for their performance. Electric vehicles, meanwhile, have become increasingly popular. A major challenge for automobile designers is to develop battery technology that will allow them to run for long periods of time while providing the range and acceleration of a gasoline-powered car. This will require substantial investment in research and development as well as a commitment from governments to promote clean-energy technologies. A robust automobile industry is vital to the United States economy, supporting nearly 9.7 million direct, indirect and induced jobs. It also contributes $702 billion in wages to Americans annually. It exports vehicles or parts to 206 countries around the world.
