Automobiles are vehicles that run on roads, usually powered by an internal combustion engine and able to carry passengers. They are of many different types based on their shape, size, propulsion system, Engine type, Engine position, Drive type and layout. Most modern automobiles are powered by gasoline-fueled, water-cooled, piston-type internal-combustion engines with their power being transmitted to the front or rear wheels or to all four of them. Diesel engines, which burn a heavier fuel, are generally employed for trucks and buses and in some passenger cars.
The invention of the automobile brought enormous changes for industry and everyday life in the twentieth century. It gave people more freedom to move and to change jobs. It caused the development of highways and other infrastructure, and it led to the growth of industries like oil, gas and rubber and new services like hotels and motels, restaurants, amusement parks and other recreation, and retail stores. It also caused problems such as pollution and the loss of undeveloped land.
Automobiles made it possible for families to travel long distances to see relatives and friends, and they are used for business travel. However, they are not as fast as airplanes and can be dangerous if not driven carefully. In addition, they consume a lot of gasoline and produce large amounts of carbon dioxide, which is a greenhouse gas. This is a major problem for the environment. People can limit the effects of this by driving a car that uses less gasoline and keeping it in good condition.