Automobiles, also known as automobiles or cars, are wheeled vehicles for carrying passengers. They usually have four wheels and are powered by an internal combustion engine fueled most commonly by gasoline (petrol), although some use other fuels and even electricity. The modern automotive industry is one of the largest and most significant in the world. Its products have transformed American and many other societies, and have shaped urban and rural development and distribution of goods, services, recreation and vacation travel.

Automobiles are so ubiquitous that few people can imagine life without them. Cars are used to commute to work and school, for shopping and family trips, and to transport goods. The automotive industry employs thousands of workers worldwide. The cars themselves provide a form of transportation that is comfortable, affordable, safe and convenient. The automobile has also given us a way to escape from the daily grind and enjoy the countryside.

Despite this freedom of movement, there are some problems associated with the automobile. Air pollution from exhaust, traffic congestion and accidents can be a real nuisance. Moreover, the automobile encourages sprawl (the spread of low-density development that degrades landscapes and produces traffic jams).

The modern automobile has developed into a complex technical system. Its components have specific design functions, and are grouped into subsystems such as suspension and steering systems, power train, electrical and electronic systems, and bodywork. Its design is determined by such factors as fuel economy, emissions control systems and safety requirements. Its production requires extensive employment of mass-production techniques, and it is a major source of employment around the world.

In the first decade of the twentieth century, the United States dominated automobile manufacturing. Henry Ford innovated mass production techniques that became standard, and he formed the “Big Three” of automakers — Ford, General Motors and Chrysler — by 1920. The booming automobile industry stimulated the growth of cities, and it helped create a middle class in the United States. It has changed the lives of millions of Americans and influenced the development of entire nations.

The modern automobile is a complex technical system that has evolved over the centuries. Originally, it was invented as an alternative to horse-drawn carriages, but eventually grew into its own sophisticated system of transportation and commerce. The automobile has become a powerful force for change in society, but it is now melding into a new age of electronics. The future of the automobile is an area of continuing research and development. Inventors are working to improve its performance, comfort and convenience while reducing the environmental impact. They are introducing new materials such as high-strength plastics, advanced alloys of metals and the electric drive.