Automobiles are self-propelled vehicles that carry passengers and are used for land transport. They usually have four wheels and use an internal-combustion engine for power. They are a vital component of modern civilization, serving as transportation for work and recreation, and delivering goods to market. The automobile industry provides jobs in manufacturing, sales and repair, and contributes to the economy through purchases of fuel and other materials.

The first cars were little more than motorized horse buggies, with engines added to the rear of a carriage. These early “horseless carriages” were expensive, unreliable and dangerous. By the end of the 19th century, however, automotive technology was improving rapidly, and manufacturers were able to produce more sophisticated designs. A major breakthrough came when Ransom Olds invented the concept of interchangeable parts and the assembly line. This allowed cars to be built at lower cost and brought them within the range of middle-class Americans.

As a result of this development, the demand for automobiles skyrocketed. The resulting increase in traffic on public roads meant that many cities had to expand their streets and highways, one of the largest expenditures by government at the time (see Transportation). Automobiles also stimulated participation in outdoor recreational activities and led to the growth of related industries such as roadside restaurants and motels. In addition, they ended rural isolation and brought urban services to rural areas such as schools, hospitals and banks (see Agriculture).

The automobile had a significant impact on the way people live their lives. It provided them with greater freedom and the ability to travel and visit friends or relatives far away. It allowed for work to be done at home instead of going into the office, and it gave women a chance to participate in public activities such as political campaigns. For example, Nell Richardson and Alice Burke made a bold car trip across the country in 1916 to advocate for women’s right to vote. They drove around with banners reading “votes for women.”

Today, there are about 1.4 billion passenger cars in operation worldwide. These vehicles consume vast amounts of gasoline and other fossil fuels, causing air pollution, congestion and climate change. Some people have chosen to drive electric cars, which are less polluting than regular gasoline-powered automobiles. Other people have switched to mass transportation systems such as buses, trains and subways, which can move large numbers of people more quickly than individual automobiles.

Although the automobile has a huge number of advantages, it is not without problems. It can be dangerous to operate and maintain, it causes millions of injuries each year, it eats up a lot of space in urban centers and its use drains dwindling world oil supplies. Because of these disadvantages, there are many efforts to make the automobile more efficient and safer. This includes more efficient engines, better safety features and less dependence on oil. New technologies have also been introduced such as electronic controls and advanced braking systems.