Automobiles are the most common form of personal transportation, with an annual production worldwide exceeding 73 million units in 2017. The automobile is a four-wheeled motor vehicle for passenger transportation that has internal combustion engines (fueled mostly by gasoline, a liquid petroleum product). Cars also have transmission systems to convert the engine’s mechanical energy into forward and reverse motion. Modern cars are equipped with service and maintenance systems, electrical equipment, and comfort devices to facilitate transportation and travel.
The automobile has become a symbol of modern society and its promise as well as the perils it poses. The development of the modern automobile, perfected in Germany and France toward the end of the nineteenth century by Gottlieb Daimler, Karl Benz, and Nicolaus Otto, has brought us freedom of movement and increased social contacts. But it has also increased the dangers of traffic accidents, crowded highways, and air pollution. It has brought new problems of economic distribution, with urban centers growing at the expense of rural areas, and it has strained the nation’s resources, particularly if one is driving a large, fuel-guzzling “road cruiser.”
Cars are divided into classes based on their use: road vehicles, off-road vehicles, and special (fire, sanitary, mobile crane, etc.). The design of automobiles varies according to their intended use. For example, a vehicle for off-road use must have durable and simple systems to withstand severe overloads and extremes of operating conditions, while high-speed automobiles need passenger comfort options and optimized handling and stability.
The earliest automobiles were essentially wagons with steam engines attached, but these were heavy and slow. The advent of the internal combustion engine in the late 1800s made automobiles more practical and quickly popular. Henry Ford innovated mass production techniques in the early twentieth century, allowing him to sell millions of his Model T automobiles at reasonable prices, and other companies adopted these methods as well. Cars became easier to operate and more comfortable as they were improved by such developments as electric ignition, the self-starter invented by Charles Kettering, and independent suspension. After World War I, steel bodies and heaters became commonplace.
Today, automobiles have evolved to include sophisticated electronics, and safety and environmental concerns are increasingly important. The era of the flamboyantly styled, gas-guzzling road cruisers is ending with the imposition of federal standards for safety and emissions, the increasing cost of oil, and the penetration of fuel-efficient, functionally designed cars from other countries. These changes are reshaping the automobile industry and changing the way people travel. As people have become more mobile, automobiles have opened up many new opportunities for employment and recreation, and allowed households to move across the country more easily. They have also influenced the development of suburbs, and have stimulated outdoor recreational activities and spurred the growth of travel-related industries such as restaurants, hotels, service stations and highway construction. It is estimated that the average American drives about 1,400 miles each year, and this number continues to rise.