Automobiles are self-propelled vehicles that are used for transportation of people and goods on roads. They are designed to run primarily on road systems, and most of them have seating for one to seven passengers.

The basic structure of an automobile includes a body, chassis and engine. Some automobiles have a roof (in a convertible) or special braking and propulsion systems, and some models may be built with three or more wheels.

Cars, buses and trucks are the most common type of automobile. Others include motorcycles, motorized bicycles, boats, and other forms of vehicle.

Automobiles are classified according to their intended purpose: Passenger vehicle, Commercial or Goods Vehicle or Special Purpose Vehicle, which includes Ambulance, Fire brigade, Police and other public vehicles.

Personal automobiles are expensive to own, and a variety of costs are associated with driving and ownership including fuel, maintenance, insurance, taxes, depreciation, parking fees, tire replacement, etc. These costs also include societal costs related to pollution and health care costs due to accidents.

Increasingly, automobiles have been redesigned with new technology in mind. They are more powerful, safer, handle better and are more eco-friendly than their predecessors.

The automobile industry is one of the world’s largest manufacturing industries, with an estimated global output of 73 million cars in 2017. It is one of the most common and universal of all modern technologies and is manufactured by companies in Europe and Asia.

The most important part of an automobile is the engine, which provides motive power to the vehicle. The engine is usually a gasoline-fueled internal combustion engine, but may be powered by other fuels such as steam or diesel. The power of the driving motor varies from less than 50 horsepower for earlier models to over 200 HP for larger models and high-performance sports or racing cars.