Automobiles are four-wheeled vehicles used to transport people and goods. These vehicles are complex technical systems that rely on thousands of component parts to operate.

They are mainly propelled by an internal combustion engine which is powered by volatile fuels like petrol, diesel, CNG, etc. In recent years, technological development has led to the use of alternative fuels like electric power and hydrogen for powering automobiles.

Cars are one of the most important inventions of the twentieth century and changed many aspects of American society. They offered a sense of independence and individuality that made it easier for Americans to commute and live their lives independently.

A modern automobile is a self-propelled vehicle that has a drivetrain consisting of an internal combustion engine, a transmission, and other components such as the brakes, suspension, steering, lights, tires, and fuel tank. There are various types of cars including passenger cars, commercial vehicles, and special purpose vehicles such as ambulances.

Cars are one of the largest sources of greenhouse gas emissions in the United States, and they emit more pollution than trains, buses, planes, and taxis combined. This is because cars run on gasoline, which releases carbon dioxide into the atmosphere. However, drivers can limit their carbon footprint by choosing a fuel-efficient vehicle and maintaining it properly. Also, drivers can reduce their emissions by riding public transportation and walking or cycling to get around.