Automobiles are complex machines that run on engines, use electricity for lighting and other systems, and move on wheels. They also carry passengers, so they have to be safe. Automobiles make modern life possible by providing people with freedom to move wherever they want and whenever they like. They allow families to go on vacation together, students to travel for school and businesspeople to get to work. Millions of people worldwide have jobs in factories that produce cars and millions more at gas stations, restaurants or motels where travelers stop. However, cars have caused many problems too. They kill people in car accidents and pollute the air that we breathe. They also cause traffic jams and take up a lot of parking space in cities.

The first automobiles were made in the 1800s, when inventors were working to develop a machine that would replace the horse-drawn carriage. Two kinds of cars were developed: steam cars, which used a water-powered engine that burned coal, and battery electric cars that ran on a chemical energy that came from batteries. The gasoline-powered cars won out, and manufacturers began churning them out. By 1920, American manufacturers were selling more than a million cars every year.

Automakers improved cars with new features after World War II. Power steering and power brakes were added. Cars were bigger and used more fuel in those days when oil was cheap, but as oil prices went up in the 1970s, companies worked on cars that used less gas.

There are now more than 1.4 billion cars in operation worldwide. Most are passenger cars that carry one to six people. There are also trucks, vans and sport utility vehicles (SUVs), which can carry more people or haul heavy loads. Special automobiles include cranes at construction sites, fire engines and patrol cars that help to keep the highways safe.

Most modern cars have safety features, such as seat belts that keep the passengers secure and airbags that protect them in case of an accident. They also have a dashboard that shows the driver how fast they are going and other information about the vehicle.

Engineers are always working on new ways to improve the automobile, making it faster and better. They are also exploring alternative sources of power, such as biodiesel and hydrogen fuel cells. Some day the cars may even be able to drive themselves!