Automobiles are vehicles powered by internal combustion, usually using gasoline but sometimes diesel or kerosene. A fuel is pumped into a cylinder, ignited by an electric spark, and the resulting explosion pushes down on a piston that turns the wheels of the car. As the engine operates, it releases exhaust into the atmosphere, which contains substances that are harmful to human health.

Although many scientists and engineers worked on automobiles throughout the nineteenth century, Karl Benz is often credited with inventing the modern automotive industry. His Benz Patent-Motorwagen ran on a four-stroke internal combustion engine, and it was the first modern motorcar to be made commercially viable.

The advent of the automobile changed many aspects of American life. It sparked the growth of industries to produce the components that make up the cars and the raw materials used for their assembly. It also brought new services like gas stations and roadside restaurants. It ended rural isolation and helped urbanize America’s population, while at the same time encouraging recreational activities like camping, fishing and hunting. It prompted new government expenditures for highway construction, and it introduced new laws like seatbelts and driver’s licenses. It also had adverse environmental impacts, with air pollution and the destruction of undeveloped land.

Some of the early automobiles were steam-powered, but they were slow and inconvenient to operate. Others were run by electricity, but they could not reach very high speeds and required frequent recharging. By the late 1890s manufacturers were producing cars that used an internal combustion engine. These were faster and more convenient to operate, but they still burned a significant amount of fuel.

By the early 1910s Henry Ford had transformed the automobile industry. He invented the modern manufacturing technique called the assembly line, which sped up production so that automobiles could be sold to a much wider range of consumers. He paid his workers a relatively high $5 a day salary, which was a great deal more than most American laborers earned. The lower cost of the Ford Model T made it possible for middle-class Americans to own and use their own cars.

Automobiles have dominated the transportation industry for most of the twentieth century and continue to do so today. There are currently more than 1.4 billion automobiles in operation worldwide. The vast majority of them are passenger cars, with the rest being trucks and buses.

In the future, researchers are seeking ways to reduce the environmental impact of automobiles while making them more energy efficient. New technologies are being developed to enable them to run on renewable fuels such as ethanol and electricity, as well as to produce less exhaust. They are also being designed with lighter materials, such as aluminum for pillars, structures and paneling. In addition, they are being designed to be more aerodynamic, so that they can travel further on a tank of fuel. It is anticipated that automobiles will continue to dominate transportation for the foreseeable future, as they offer people more freedom and control over their schedules than any other form of transport.