Automobiles are four-wheeled vehicles designed to carry passengers. Most of them are powered by an internal combustion engine, which uses gasoline (or other fuels such as diesel or kerosene) to turn the wheels. The engine gets its energy from chemical energy in the gasoline or other fuel when it is burned. This energy moves the wheels by a system of levers and pulleys called an automotive drive. The power of the engine is measured in kilowatts (or horsepower).
The automobile has brought many changes for industry and technology, as well as for everyday life. It has spawned new industries such as petroleum and gasoline, rubber and plastics, as well as services like gas stations and convenience stores. It also has helped make modern work possible, allowing people to live and work in different places.
Today, over 1.4 billion passenger cars are in use. Most of them are in the United States, where people drive more than three trillion miles (five trillion kilometres) each year. The automobile has become the primary mode of family transportation, and manufacturers offer hundreds of models to choose from. These cars range from the advanced design of the 1901 Mercedes to the tiller-steered, one-cylinder, three-horsepower Oldsmobile that first appeared in 1904.
Having your own car makes you more flexible and gives you the freedom to travel as you want. However, driving can be dangerous if you are not careful and follow the rules of the road. It is also important to consider the impact of your vehicle on the environment.