Automobiles are wheeled motor vehicles that carry passengers and usually a cargo. They have four to eight wheels and are designed for use primarily on roads. They are powered by internal combustion engines (using volatile inflammable fuel such as gasoline, petrol, alcohol or naphtha) or electric motors. They have a wide range of sizes, speeds and styles and can be designed for general transport or specific purposes such as military or emergency services.
The earliest automobiles were steam, electric or battery-powered and had limited range. Gasoline cars became popular in the 1910s and quickly replaced animal-drawn carriages. Today automobiles are built to be safe, convenient and comfortable. Some automobiles have features like air bags and crumple zones that reduce the chances of injury in a crash. Others offer conveniences like cup holders and power windows. Modern vehicles also feature entertainment systems and navigational aids.
There are many benefits of having an automobile: independence and freedom to travel anywhere without waiting for others, or worrying about making it to a bus stop in time. However, automobiles have other drawbacks: they can be expensive to buy and maintain; can damage buildings or other objects on the way; cause pollution that causes climate change; and they create traffic congestion when too many people try to drive in the same area.
The branch of engineering that deals with the design and manufacture of automobiles is known as automotive engineering. Automobiles are the most common transportation vehicle in the world. They have a major impact on society and the economy.