Automobiles are motor vehicles designed for transporting people and things. They are often fueled by gasoline and may also be powered by other fuels such as propane, methanol, hydrogen, and natural gas. They are often designed to carry heavy loads and to travel long distances at relatively high speeds. They are usually driven by humans, although robotic and computer-controlled vehicles are now available. The invention of the automobile brought many changes to industry and technology, as well as to everyday life in the United States and around the world. It opened up new areas of freedom and mobility to individuals who did not previously have access to affordable personal transportation. Industries and services grew to provide the necessary parts, components, and fuel for the vehicle.

In the beginning, it was expensive to produce an automobile. As the market developed, however, engineering improved to lower costs and increase production. The development of the assembly line, introduced by Ransom E. Olds in 1902, and later expanded by Henry Ford in the 1910s, enabled automobile manufacture to enter the mass-production market. This was the most important change in the automotive industry.

Throughout the history of the automobile, manufacturers have been forced to constantly improve and refine their products in order to keep pace with competitors. As a result, many new developments have occurred that have improved the quality of the car. For example, safety systems have been improved to prevent accidents, and electronic controls allow cars to be operated with greater ease and control. In addition, many different methods have been used to make the car more efficient and economical. For example, electric ignition and the electric self-starter, invented by Charles Kettering for the Cadillac in 1910-1911, and independent suspension are just two examples of technical improvements.

Other improvements have included the use of steel alloys to reduce weight, reducing the size and complexity of mechanical parts, improving passenger comfort, and optimizing performance on limited-access road systems. The design of an automobile depends to a large degree on its intended use, which influences features such as transmission type and capacity, engine power and speed, suspension, weight distribution, stability, safety systems, and ergonomics.

The era of the annually restyled “road cruiser” came to an end with federal standards for safety, emissions, and fuel efficiency; with escalating oil prices, and the drain on dwindling world supplies; and with the entry into the American and world markets of compact, functionally designed, economical Japanese cars.

Exactly who invented the automobile is an ongoing debate. Leonardo da Vinci is often given credit for designing and creating prototypes of transport vehicles, but it was Gottlieb Wilhelm Daimler, a German industrialist and engineer, who invented the first gas-powered internal combustion engine in 1885/1886. This engine was then fitted to a carriage and used in a vehicle. Its success made the automobile a popular mode of transportation in the United States and around the world.