An automobile, also called a motor car or a car is a powered road vehicle with four or more wheels that is used for transportation. Most modern automobiles burn a fuel to make an internal combustion engine (sometimes called a motor) run and then send the power through a set of gears to drive the wheels. The most common fuel is gasoline, a liquid product.

Automobiles are important in the United States because they give people freedom to travel and work without having to rely on public transportation or other people. People who live in suburban or rural areas often need a car to go to work and to store things they need.

The cars in the early 20th century were big, heavy and expensive. Some of them had very few features. Most people could not afford them. But in the 1920s, a few innovations made them more affordable and easier to use. These included the self-starter, the closed all-steel body and the hydraulic brakes.

By the 1930s, most families had an automobile. They drove more than 4.8 trillion kilometers (three trillion miles) in a year. Modern life became inconceivable or at least highly inconvenient without access to one. Industries developed to make parts and services such as gas stations. And jobs created to build and maintain the vehicles.

Today’s cars have many advanced features. For example, they can automatically brake when another car pulls in front of you. They also have a system that warns you when the tires are low on air. They are becoming more computerized so they may eventually drive themselves on highways and other roads.

The scientific and technical building blocks for the automobile were laid in the late 1600s by Christiaan Huygens, who invented a type of internal engine sparked by gunpowder. But it took a long time for these ideas to be put into practical applications. The first commercial automobiles ran on steam, electric power and gasoline. Steam vehicles could reach high speeds but were slow to start. Battery-powered electric cars had a limited range and recharging stations were hard to find. Gasoline-powered cars soon won out.

In 1908, Ford introduced his Model T, a car that was inexpensive enough for middle-class Americans to own. By the time it was withdrawn from production in 1927, 15 million had been sold. In addition to simplifying the design and lowering prices, Ford innovated modern mass production techniques by using assembly lines at his factories. These used conveyor belts to move workers and parts through the process.

Several Japanese companies began making automobiles after World War II. These included Nissan, Suzuki and Honda, which all started as manufacturers of other goods before the war. Today, most cars in the United States are made by American and European manufacturers. But many other countries now produce them too. The biggest company is Toyota.