Automobiles are wheeled vehicles that carry passengers and use motor power to move. They are designed to run primarily on roads and have seating for one to seven people, depending on the vehicle type. Automobiles have a variety of uses, including private transportation, business and industrial deliveries, and public services such as police, fire, ambulance and utility vehicles. They also provide transportation for recreational activities such as vacation travel and dining out. The automobile has had a profound influence on human life in modern times, and continues to impact the economy, culture and society of many countries worldwide.

Almost all contemporary automobiles use an internal combustion engine to provide the energy to turn the wheels of the car and move it forward. The engine burns a fuel — usually gasoline but sometimes diesel or kerosene — to generate energy to drive the car and propel it forward. The engine is usually located in the rear of the car, between the wheels. Its output is measured in kilowatts or horsepower, the latter being the measure of how much energy it produces.

The rest of the vehicle is attached to the chassis, a frame that is designed to support the various systems and components of the car, such as suspension, steering and braking. The body, which is made of a metal or composite material such as fiberglass, serves a number of purposes, including providing safety for the passengers and protection from the elements. The front of the body is designed to crumple in a crash, absorbing much of the force. In addition, the hood and the firewall between the engine and passenger cabin are designed to prevent fire in the event of an accident.

During the late nineteenth century, inventors created a wide variety of automobiles. Some were simply horse-drawn carriages fitted with engines, while others were designed from scratch. Karl Benz of Germany is generally credited with inventing the first true automobile, using an internal combustion engine, in 1885 or 1886. Gottlieb Daimler, of the same country, later converted a bicycle into a motorized vehicle, though this was not an automobile.

Since the 1920s, most cars have been mass-produced and sold in a range of prices, from affordable models to luxury vehicles. In order to compete with each other, manufacturers have sought to improve the design of the engine, chassis, transmission, safety and security features, electrical systems and the body. Research and development engineers have been instrumental in the advancement of these technologies. As an example of this competition, the assembly line approach to car manufacturing was introduced by Ransom Olds in 1902. This concept has helped the industry develop rapidly.