A modern automobile is a complex technical system of interrelated subsystems with specific design functions. Its component parts may consist of thousands of components that have evolved from breakthroughs in existing technology or are the result of new technologies such as electronic computers and high-strength alloys of steel and nonferrous metals. It is designed primarily for passenger transportation and usually is powered by an internal-combustion engine using a volatile fuel.

Automobiles have become the principal means of transportation for people in most industrialized countries. They carry more than three trillion miles (five trillion kilometres) per year, mostly in the United States.

They are the most widely used and versatile human-powered vehicles ever invented, with the exception of bicycles. They can transport one or more occupants, can be driven on roads, are relatively safe, and can accelerate to high speeds with relative ease. They have revolutionized the way people live by providing them with greater freedom than previous forms of transport. They also allow people to make more trips than they could with public transportation and can be more easily loaded with cargo than trailers or ships.

The modern automobile was developed in the late nineteenth century by such innovators as Gottlieb Daimler, Karl Benz, and Nicolaus Otto in Germany, Emile Levassor of France, Charles E. Olds in America, and Henry Ford in the United States. The development of large-scale production and the assembly line made automobiles affordable to the masses, starting with Ransom Eli Olds’s Model T runabout in 1902.

Despite their convenience and utility, cars pose numerous problems for drivers and other road users. The basic safety problems include human error, mechanical failure, and the tendency of some vehicles to roll over if the forces exerted on them are excessive. In addition, air pollution and the need for a safe distance between vehicles can be problems.

Other problems of automobiles are noise, vibration, and environmental impact. The solution to these problems is to improve vehicle design and control systems, provide for safer occupants in accidents, and increase the use of alternative fuels.

The automobiles of the future may be powered by electricity, hydrogen, solar energy, tidal waves, wind power, or even garbage. Moreover, they will be lighter and more environmentally friendly. Their performance will be optimized to suit the needs of various driving conditions, from off-roading in rugged terrain to high-speed, limited-access highway systems. Moreover, they will be powered by more powerful engines and equipped with safety and comfort features. They will also be more efficient and easier to maintain. These innovations are based on the fundamentals of physics, engineering, and computer science. Nevertheless, the automotive industry continues to face challenges in developing new automobiles with improved safety and performance and meeting consumer demand. The automobile industry is also challenged by the emergence of alternative forms of transportation, such as trains and bicycles. These developments will likely affect the long-term growth of the automobile industry.