Automobiles are vehicles designed for road transportation, carrying passengers and cargo. Most automobiles are powered by an internal combustion engine fueled by gasoline or diesel fuel. There are a wide variety of automotive styles and sizes, including sedans, hatchbacks, minivans, sports cars and trucks. Some automobiles are specialized for emergency use, such as fire engines, ambulances and patrol cars.

The scientific and technical building blocks of the modern automobile go back several hundred years. Steam and electric vehicles were produced in the late 1700s and early 1800s, but these primitive vehicles did not have the range and speed of current models. In the late 19th century, German engineer Karl Benz developed the first gas-powered motor vehicle.

By the 1920s the automobile had overtaken the streets and highways of Europe and America. Henry Ford revolutionized industrial manufacturing by introducing assembly lines, and his Model T made the automobile affordable for middle-class families.

Modern automobiles are complex technological systems, with subsystems that have specific design functions. For example, a vehicle designed for off-road use needs to be capable of withstanding severe overloads and extreme operating conditions. Vehicles designed for high-speed travel need optimized passenger comfort options and advanced engine performance, while safety features include seat belts, air bags and rearview mirrors.

In the past few decades, concern about the environmental effects of automobiles and the depletion of world oil reserves has sparked new interest in hybrid, electrical and autonomous vehicles. The automobile industry has also experienced significant shifts in technology, including the introduction of electronic control systems and computerized engine management.