Automobiles are four-wheeled vehicles for transportation of people and usually propelled by an internal combustion engine using a volatile fuel. The automobile has changed many parts of society and the economy, creating new industries and jobs in the construction, manufacturing, maintenance and repair of cars and their components. The automobile also has increased the mobility of its owners, allowing them to travel farther and faster than before. The automobile has also helped change where people live, making suburbs and other rural areas more desirable than city living.
The first automobiles were invented in the late 1700s by Nicolas-Joseph Cugnot of France and others, but they were heavy and did not move fast enough for anyone to need them. In the 1890s, German inventors Gottlieb Daimler, Karl Benz and Nicolaus Otto developed internal combustion engines that made gasoline-powered cars much lighter. They still required a lot of energy to operate, however, so they were not suitable for long trips.
American automotive engineers improved on the German designs in the early 1900s, and Henry Ford introduced mass production. His Model T was an affordable vehicle that greatly expanded the number of people who owned and drove automobiles. In the United States, cheap raw materials and a tradition of mechanization encouraged car production. In addition, a large land area and relatively equitable income distribution meant great demand for automotive transportation.
A modern automobile is a complex technical system involving many subsystems that work together to meet the driver’s needs. Some of these are based on breakthroughs in electronics, computer technology and high-strength plastics. Other systems have evolved from advances in metallurgy, such as the use of more efficient alloys of steel and nonferrous metals. Other systems are the result of advances in engineering, such as electronic controls and a greater understanding of fluid mechanics and aerodynamics.
The body of an automobile, which protects and houses the mechanical elements, can be made of a variety of materials, including fiberglass and strong plastic. The frame, which supports the mechanical and electrical parts, is made of steel or aluminum. The hood, trunk and the fenders, which cover the wheels, are usually made of steel or a combination of steel and lightweight plastic. The interior of an automobile, which includes the passenger compartment and a space for the engine, is designed to provide comfort and safety. Modern vehicles have air conditioning and stereos, as well as seats that adjust to fit the passengers comfortably. Seat belts are required in most countries to help prevent injuries during a crash, and infants and children must be secured in child seats.
Besides cars that are used to transport people, there are special automobiles for use in construction and repair of other vehicles. Some are also equipped for rescue and emergency duties, such as fire engines and ambulances. Those that are driven on public roads must be designed for stability, passenger safety and comfortable, controlled handling at high speeds. Other specialized automobiles include racing cars, military vehicles and work vehicles like crane vehicles and road rollers.