Automobiles are four-wheeled vehicles designed primarily for passenger transportation and usually propelled by an internal-combustion engine using a volatile fuel. The modern automobile is a complex technical system employing many subsystems with specific design functions. Its thousands of component parts have evolved from breakthroughs in existing technology or have been incorporated by new technologies such as electronic computers and high-strength plastics. The automobile has changed society in many ways. It has provided people with more freedom and more choices as to how they live their lives and interact with others. It has also allowed them to travel farther distances and visit more places than was possible before the invention of the car.

This section will explore the major systems in an automobile including the engine, suspension system, braking system, and wheels and tires. The body, analogous to the skeleton in a human body, provides support for these systems and houses the interior of the car as well as storage and the driver.

The automobile came into wide use in the United States after being perfected in Germany and France toward the end of the nineteenth century by engineers such as Gottlieb Daimler, Karl Benz, and Wilhelm Maybach. In the United States the advent of the automobile was facilitated by Henry Ford, who pioneered an assembly line process that greatly reduced the cost of making cars. Postwar into the 1960s, the issue of automobiles was dominated by the questionable aesthetics of nonfunctional styling and concerns about air pollution and the draining of world oil reserves.