A motor vehicle, also known as motorized vehicle or automotive vehicle, is a self-propelled land vehicle, commonly wheeled, that does not operate on rails (such as trains or trams) and is used for the transportation of people or cargo. The vehicle propulsion is provided by an engine or motor, usually an internal combustion engine or an electric motor, or some combination of the two, such as hybrid electric vehicles and plug-in hybrids. For legal purpose, motor vehicles are often identified within a number of vehicle classes including cars, buses, motorcycles, off-road vehicles, light trucks and regular trucks. These classifications vary according to the legal codes of each country. ISO 3833:1977 is the standard for road vehicle types, terms and definitions. Generally, to avoid requiring people with disabilities from having to possess an operators license to use one, or requiring tags and insurance, powered wheelchairs will be specifically excluded by law from being considered motor vehicles. As of 2011, there were more than one billion motor vehicles in use in the world, excluding off-road vehicles and heavy construction equipment. The US publisher Wards estimates that as of 2019, there were 1.4 billion motor vehicles in use in the world.Global vehicle ownership per capita in 2010 was 148 vehicles in operation (VIO) per 1000 people. China has the largest motor vehicle fleet in the world, with 322 million motor vehicles registered at the end of September 2018.
A total of 11.5 million heavy trucks were registered at the end 2016 Vehicle ownership per capita in the U.S. is also the highest in the world, the U.S. Department of Energy (USDoE) reports a motorization rate of 831.9 vehicles in operation per 1000 people in 2016, or a ratio of 1:1.2 vehicles to people.According to USDoE, the rate of motorization peaked in 2007 at 844.5 vehicles per 1000 people. In terms of licensed drivers, as of 2009 the country had 1.0 vehicle for every licensed driver, and 1.87 vehicles per household. Passenger car registrations in the United States declined -11.5% in 2017 and -12.8% in 2018.As of 2016, the stock of alternative fuel vehicles in the United States included over 20 million flex-fuel cars and light trucks, the worlds second largest flexible-fuel fleet in the world after Brazil. However, actual use of ethanol fuel is significantly limited due to the lack of E85 refueling infrastructure.Regarding the electrified segment, the fleet of hybrid electric vehicles in the United States is the second largest in the world after Japan, with more than four million units sold through April 2016. Since the introduction of the Tesla Roadster electric car in 2008, cumulative sales of highway legal plug-in electric vehicles in the U.S. passed one million units in September 2018. The U.S. stock of plug-in vehicles is the second largest after China (2.21 million by September 2018).As of 2017, the countrys fleet also includes more than 160,000 natural gas vehicles, mainly transit buses and delivery fleets.