A modern automobile is a wheeled motor vehicle, usually with four wheels, designed primarily for the transportation of passengers. It is propelled by an internal combustion engine fueled by volatile inflammable liquids, most commonly gasoline (petrol), although other fuels have been used, including alcohol and naphtha. Automobiles have many features to make them safe and comfortable for transportation. They may have air conditioning, power steering and/or brakes, and seats that adjust automatically to fit the driver and passengers. In addition, the modern automobile has a multitude of electrical systems to control and operate its various functions.

The automobile is one of the most important and widespread of all modern technologies. It has had a major influence on society and culture, as well as being an essential part of the economy.

There are now more than 73 million cars on the road worldwide. Automobiles are a common sight in cities and suburban areas and are also popular with families, who often own multiple vehicles to accommodate family members and cargo. For people who work out of town or in the country, a car can be a lifesaver. It allows them to avoid relying on friends or relatives for rides to and from work, and gives them more control over their schedules.

The first modern automobiles were developed in Germany and France by Gottlieb Daimler, Karl Benz and Nicolaus Otto during the late 1800s. The development of the internal combustion engine allowed them to move at higher speeds than horse-drawn carriages and to transport passengers over long distances more quickly. By the end of the century, American companies such as Ransom E. Olds and Henry Ford had produced a great number of cars in a huge volume, far more than any other manufacturers had previously accomplished.

Automobiles can have negative impacts on the environment when they are not operated and maintained properly. They are a source of air pollution and contribute to global warming. They also cause traffic congestion when too many of them try to go the same place at the same time. This causes unnecessary wear and tear on roads and highways, and puts a strain on dwindling world oil supplies.

As technology advances, automobiles are becoming safer and more environmentally friendly. New safety systems and improved energy efficiency reduce both the cost of operation and the amount of gas needed to propel them. Improvements in design and manufacturing allow for more efficient engines, lighter bodies and better quality interiors. Automobiles are increasingly being made from high-strength steels and lightweight aluminum alloys, which are also more environmentally friendly than the heavier and less durable metals used in pre-World War II cars. During the postwar period, however, engineering was sometimes subordinated to questionable aesthetics and nonfunctional styling, and quality suffered. The result was higher unit profits for Detroit automakers but lower overall quality and increased road maintenance costs for consumers.