An automobile (or car) is a motor vehicle for transporting passengers that has four wheels and is powered by an internal combustion engine, usually gasoline fueled but sometimes diesel fuel or other liquid petroleum products. It is one of the most universal and widely used of modern technologies and represents a major industry with many ancillary and related industries.
The scientific and technical building blocks of the automobile date back several centuries. The first self-propelled vehicles were steam-powered. By the end of the 17th century they could travel at speeds up to 4 mph (7 kph) but were difficult to start and needed to be refueled often. Battery-powered electric cars had a 38 percent share of the automobile market in 1900 but were more expensive than gas-fueled cars and their range was limited. The automobile revolutionized America and other industrialized nations, leading to new jobs in dozens of industries from rubber manufacturing to road construction. It ended rural isolation and brought urban services such as medical care and schools to the countryside. The automobile also prompted urban sprawl, turning large cities into suburbs with shopping malls and office buildings surrounding residential areas.
The automobile spawned new social debates about its role in society, especially over congestion and safety issues. As American firms dominated the industry, engineering was subordinated to questionable aesthetics and nonfunctional styling, while quality declined to the point that by the mid-1960s Detroit-made cars had an average of 24 defects per model. The end of the era of the annually restyled “road cruiser” came with government regulations on safety, emissions and fuel efficiency, and a growing awareness that oil supplies would eventually be exhausted.