Automobiles are a large class of motor vehicles used for passenger transportation on land. They usually have four wheels and are powered most often by gasoline, a liquid product. The automobile, or car, is one of the most universal of modern technologies and it remains today one of the world’s largest industries, with more than 73 million new cars produced worldwide in 2017. Unlike bicycles, motorcycles and fixed-wing aircraft, they enclose their passengers in a closed compartment and provide protection from weather and other environmental hazards. They also allow for personal mobility that would be difficult or impossible with any other type of vehicle, and they can carry much larger loads than two-wheeled vehicles such as bicycles. Modern automobiles also incorporate safety features such as seat belts, airbags and crumple zones.

The history of the automobile stretches back several hundred years. The scientific and technological building blocks of the automobile can be traced to inventions such as the internal combustion engine, invented by Dutch scientist Christiaan Huygens in the late 1600s. Various inventors have contributed to the advancement of the automobile, such as Charles Duryea and J. Frank. Karl Benz is commonly credited with inventing the modern automobile, although the exact timing of his creation remains in dispute.

Initially, automobiles were powered by steam, electric power or internal combustion engines that ran on gunpowder — fuel exploded inside the engine to create fire and drive the wheel axles. Steam-powered automobiles could reach high speeds but were inefficient and had limited range. Battery-powered electric cars, which accounted for 38 percent of the United States automobile market in 1900, were fast but required frequent recharging and were impractical for use on long journeys. Gasoline-powered engines became the dominant technology by 1920 because they could achieve higher speeds and cover long distances on an economical basis.

Modern automobiles are complex technical systems that utilize a multitude of subsystems that have specific design functions. In addition, the automobile requires a number of other support systems such as fuel delivery, cooling, electrical and mechanical drive systems, steering, suspension and the like. Engineers have made many improvements to automobile design over the past century. The development of new materials such as high-strength steels, aluminum alloys and plastics has enabled the construction of lighter weight, more durable and safer automobiles. Many improvements have been a result of the impact of new laws and regulations regarding automotive safety, performance, noise, emissions and handling.

Whether or not an individual considers himself to be an automobile enthusiast, most people appreciate the convenience of being able to travel independently without having to depend on others for transportation. Whether an automobile is driven on city streets, country roads or interstate highways, owning an automobile can be a major financial commitment. However, it is an important investment that can bring a feeling of freedom and independence. It can also help to reduce reliance on public transportation, which can sometimes be unpredictable in terms of scheduling and route reliability.