Automobiles, also called motorcars or cars, are the modern vehicles that rely on an internal combustion engine, powered by a volatile fuel. An automobile is a complex technical system, comprising thousands of individual subsystems with specific design functions. Its development has spanned centuries, and the evolution of its components has been driven by scientific breakthroughs in the fields of electronics, high-strength plastics, and new alloys of steel and nonferrous metals.

Despite the earliest car designs that used steam, electric power, or a combination of both, it was the introduction of the gasoline-powered automobile that proved most successful. Its market penetration was facilitated by three factors: the large size of the American population, its vast geographical area, and cheap raw materials that allowed the production of the vehicle at prices far below those in Europe.

The first true automobiles were perfected in Germany and France toward the end of the 1800s by such engineers as Gottlieb Daimler, Karl Benz, and Nicolaus Otto. Their engineering innovations included the first self-starting engines, closed all-steel bodies, and the four-stroke, two-cylinder engine with a continuous flow of fuel. But it was the businessman and engineer Henry Ford who truly revolutionized automobile production. He developed assembly line manufacturing, which lowered the cost of production until it could be within reach for most middle-class families.

After World War II, automakers funneled their resources into military production and sales of passenger cars slowed down. By the 1960s, market saturation combined with technological stagnation: Innovation was incremental rather than dramatic. The advent of federal safety and pollution standards, the draining of world oil reserves, and escalating gas prices helped resurrect demand for small, functionally designed cars. This led to the rise of Japanese manufacturers, which introduced fuel-efficient, well-built, and aesthetically pleasing small cars that displaced their American competitors.

Today, cars are available in a wide range of sizes and price ranges. The most popular types are sedans with four doors and a traditional trunk, followed by SUVs with three rows of seats and a large cargo hold, and then luxury cars from Mercedes-Benz, BMW, and Lexus. The current generation of the automobile is an objective improvement over its predecessors in nearly every measurable way: it’s more powerful, faster, safer, and easier to handle. It keeps occupants more comfortable, and it uses a lot less energy. The automobile is the most important technology of our time. It is a vital part of the economy, and it allows people to live independently, go places they couldn’t before, and achieve dreams that they never thought possible.