Automobiles are four-wheeled motor vehicles that run primarily on roads, seat one to eight people and have the ability to transport cargo. They are powered by either internal combustion (gasoline or diesel) or electric power, and their propulsion systems may use one or more wheels to generate torque and drive the vehicle forward or backward. An automobile is usually equipped with a gearbox to transmit engine torque to the road wheels, steering and brakes.

The modern automobile was developed and perfected in Germany and France in the late 1800s by such pioneers as Gottlieb Daimler, Karl Benz and Nicolaus Otto. American inventors soon surpassed European manufacturers, however, with the introduction of Henry Ford’s assembly line and the mass production of inexpensive Model T cars. The American manufacturing system proved highly successful, and by the 1920s Ford, General Motors and Chrysler were the biggest automakers.

The automotive industry was shifted into high gear during World War II as companies turned out millions of military vehicles and other war materials, producing a total of about one-fifth of the nation’s war production. Postwar the industry was challenged by nonfunctional styling, quality issues and environmental aspects involving the draining of oil resources and resulting pollution of air and water. In response, the market shifted from the low-priced monopoly of the American manufacturers to a competitive buyer’s market with the advent of small, fuel-efficient cars produced by German and Japanese automakers.

Aside from their role in everyday transportation, automobiles are used for racing and other special purposes. Cars are also used for emergencies, such as fire engines, ambulances and police patrol cars. The automotive industry also produces specialized automobiles, such as crane vehicles, mobile homes, snowplows and fork-lift trucks for work sites.

In the 21st century, automobile technology, safety features and design have continued to advance rapidly, changing our lives in fundamental ways. They have become a ubiquitous part of our culture, serving not just as personal transportation but also as a conduit for shopping and social interaction. In addition, the automobile has served as a catalyst for many new social and economic changes.

The automotive industry is responsible for a considerable amount of greenhouse gas emissions, so there are concerns about the impact on the environment and climate change. Some consumers prefer to reduce their carbon footprint by using hybrid cars, which combine the gasoline and electrical power of an ordinary automobile with the fuel efficiency of a smaller car. Others, though, believe that the automobile is not as environmentally friendly as other forms of transportation such as trains or planes. As a result, some consumers have stopped purchasing automobiles or have begun to limit their usage, and the number of automobiles on the road has decreased over time. This has led to a decrease in traffic congestion and an increase in safety on the road. The decline of the automobile may ultimately lead to a shift toward other forms of transportation.