Automobiles are machines that are self-propelled and wheeled and powered by an internal combustion engine. People use automobiles for a wide variety of transportation needs. Today, there are 1.4 billion passenger cars in use worldwide, with one-quarter of those being in the United States. These vehicles travel over three trillion miles each year, and half of them are manufactured by foreign companies. Manufacturers continue to innovate, introducing new designs more frequently.


Self-propelled automobiles are vehicles that use energy to propel themselves. They use a variety of methods to achieve this, including batteries and internal combustion engines. Most self-propelled automobiles use internal combustion engines, which burn flammable gases and liquids to produce mechanical motion. They can also be used in machinery to turn crankshafts and generate electricity. Another option is to use steam engines, which produce movement by sucking water from the surrounding air and converting it to steam.


Wheeled automobiles are vehicles with two or more wheels. These vehicles are often used for recreational purposes and are popular in some jurisdictions. Some of these vehicles are regulated like motorcycles, but they are generally more fun to drive than four-wheeled automobiles. Some of the most popular three-wheeled models are reverse trikes and open-air roadsters. They are usually made with one wide drive wheel in the rear and two pivoting nondrive wheels up front.

Driven by an internal combustion engine

An internal combustion engine is an engine that burns fuel to produce electricity. The first internal combustion engine was invented by Francois Isaac de Rivaz in 1807. This engine worked with hydrogen fuel and used an electric spark to ignite fuel. It was installed in a working vehicle in 1808. A century later, Samuel Brown patented a version of the internal combustion engine that could be used for industrial purposes.

Safety features

Modern cars come with numerous safety features to help prevent accidents. These features are usually camera-based and can warn the driver of an impending collision. They can also prevent accidents by alerting the driver if another vehicle is about to cross the road.