Automobiles are motor vehicles used primarily to transport people. The word automobile derives from the Greek prefix auto (self) and Latin formobilis (to move). Modern cars are complex technical systems that employ many subsystems, including those that control the car’s engine, transmission, chassis, bodywork, electrical equipment, and service devices. In addition to the basic power unit (engine), these systems often rely on advanced technology, such as electronic computers, high-strength plastics, and new alloys of metal. During the last century, automobile production became one of the world’s largest industries.

The automobile revolutionized 20th-century society by enabling individuals to travel long distances at relatively high speeds. It stimulated participation in outdoor recreation and spawned tourism-related businesses such as motels and restaurants along highways. It ended rural isolation and brought urban amenities, such as hospitals and schools, to agricultural communities. It fueled the growth of cities, which in turn fueled the expansion of suburban residential areas. It boosted the economy by providing a major source of employment and stimulating the demand for steel, petroleum products, and other industrial goods. It also boosted the construction of roads and highways, which became one of the largest items of government expenditure.

Automobiles were first developed in the late 1800s. They are powered by an internal combustion engine using a volatile fuel such as gasoline, diesel fuel, or kerosene to provide the energy that drives the vehicle’s wheels. Most have four wheels and are driven by a crankshaft attached to an axle. The automotive industry is a huge business and produces billions of dollars worth of machines each year.

Some early automobiles were powered by electricity, but this type of vehicle was slow and bulky and soon went out of favor. The development of a practical, fuel-efficient steam engine during the 1850s allowed for the creation of a variety of road vehicles that were much faster and more comfortable than earlier models.

An automobile has become the dominant mode of transportation in most countries. It allows people to live and work in different places, thus increasing their options for relationships and careers. This freedom to travel also opens up the possibility of visiting relatives in distant locations and participating in many other activities that would otherwise be impossible or at least very difficult to do.

Despite their convenience, the automobile brings with it many disadvantages that need to be addressed. Some of these problems are related to the environment, including pollution and noise. Others are social, such as the potential for accidents that can injure or kill people and damage property. People’s attitudes toward driving also need to be considered, as do laws governing the use of vehicles on public roads. The automobile has a great future in the United States and elsewhere, but it also faces serious challenges from newer technologies. For example, the electric car has emerged as a viable alternative to the conventional gasoline-powered automobile. Manufacturers are working to produce vehicles that are more efficient, safe, and environmentally friendly.