Automobiles are wheeled passenger vehicles designed to run mainly on roads and carry one to seven people. Most automobiles are powered by internal combustion engines (combustion of gasoline, diesel, hydrogen), although there are a few electric and other alternative fuel cars. They are the primary mode of transportation for most of the world’s population and transport more than three trillion kilometers (over five trillion miles) every year on average. Automobiles are also a significant source of pollution and greenhouse gases, especially in the United States where they account for 27 percent of national emissions of carbon dioxide.

In the 1700s and 1800s, steam and electrically powered cars were developed for racing and amusement, with the first gas powered vehicles emerging in the early 1900s. The introduction of production methods by American Henry Ford made automobiles affordable for middle-class families and ushered in the age of the modern car.

The auto industry contributes significantly to the economy. It is a major consumer of steel, oil and other raw materials and employs millions of workers worldwide. It is also the primary customer of many ancillary industries, such as those producing tires, spark plugs and exhaust systems.

The automobile is considered to be the most important invention in human history and has revolutionized the way the world lives. It has allowed people to live farther from work and to engage in more leisure activities. It has also shaped urban development, and spawned a number of service industries, such as garages, repair shops, insurance companies and gasoline stations.