A vehicle is any machine that transports people or cargo, although this term most often refers to cars, trucks and SUVs. These vehicles have been in commercial production for more than a century and are most popular in developed nations. A car primarily uses fossil fuels, although some modern cars use alternative fuel sources as well.
A car is the most common term for a wheeled motor vehicle in the United States, but it is also known as an automobile, auto. Cars are generally designed to travel on public roads. They usually have four wheels and have a seating capacity for two to six people. While cars usually transport people, trucks are more likely to transport cargo. Gasoline and diesel have been the most common fuels for cars throughout history, although the specific composition of these fuels has changed significantly. The amount of pollutants, especially greenhouse gases, produced by a car with an internal combustion engine has been steadily decreasing. Alternative fuels used by cars include hydrogen, electricity, ethanol, and compressed natural gas (CNG).
The first cars of practical value were made in the late 1890s and improved rapidly with a series of updates by various inventors. The first mass-produced model was the Oldsmobile Curved Dash, released in 1902. Henry Ford greatly improved the mass-production techniques for cars in 1914. The number of cars in the world was about half a billion in 1986, and increased to one billion by 2010.
The primary benefits of a car include convenient and independent transportation upon demand. This must be measured against the cost of owning a car, which includes the price of the vehicle itself, maintenance, fuel, depreciation and insurance.
Consumers typically purchase a car through a car dealer, rather than directly from the manufacturer. In addition to selling, car dealers typically carry parts and provide maintenance and repair for the cars they sell. New cars routinely come with warranties that cover many types of repairs for a specific amount of time or mileage on the car. Fuel stations that sell gasoline and diesel are readily available, but cars that use CNG and hydrogen have limited refueling options.
Cars are often in economic competition with forms of public transportation, such as buses and trains. Because they require more land in the form of roads and parking, cars are generally more economical to use when the population density is low. The cost savings of mass transportation must be weighed against the disadvantages, which include the inconvenience and time spent waiting for the bus or train.
The basic mechanical operation for cars with internal combustion engines has remained relatively unchanged throughout history, although performance and fuel efficiency has improved dramatically. Modern vehicles also use computerized technology for a variety of purposes, such as engine control, navigation, and entertainment. Alternative fuels that are less harmful to the environment are beginning to replace fossil fuels, although cars that use alternative fuels are still in the minority.