Automobiles, or motor cars, are four-wheeled vehicles that carry passengers and small amounts of cargo. They are the principal means of transportation in most industrialized nations, with 1.4 billion in operation worldwide and about 70 million new ones built each year. Their rapid and flexible mobility has reshaped societies, while also degrading landscapes. They have become the symbol of the promise and pitfalls of modern technology, especially as they allow people to move rapidly across long distances and avoid being dependent on time-consuming public transportation.
The design of an automobile depends to a large extent on its intended use. It must have durable, simple systems that are resistant to extreme overloads and operating conditions. It must be able to perform at high speeds, while providing passenger comfort options and optimized handling and stability.
Some of the major systems of an automobile include the engine, transmission system, electrical and auxiliary equipment, cooling and lubrication, chassis, and wheels and tires. The design of these systems is a trade-off among competing factors, since each one has an impact on other aspects of the vehicle.
The earliest self-propelled vehicles were steam-powered. Nicolas Cugnot built a three-wheeled, steam-driven carriage in Paris in 1769; Samuel Brown tested a steam-powered car in 1826. In 1870, Siegfried Marcus of Austria developed a two-stroke internal combustion engine that powered a handcart. Gottlieb Daimler of Germany modified an existing horse-drawn carriage in 1886 with a four-stroke, gasoline-powered engine and exhibited it in Paris in 1889. Emile Levassor and Armand Peugeot of France began producing automobiles with Daimler engines in 1890, which helped lay the foundation for the French auto industry. Henry Ford’s introduction of the assembly line in 1913 enabled the mass production of Model T cars, making them affordable to middle-class American families.