Big rigs, also known as semi-trucks or tractor-trailers, are large vehicles designed for transporting goods over long distances. They consist of a powerful front unit, called the tractor, which pulls a separate trailer that carries cargo. These trucks are essential for the freight transportation industry, moving everything from food to electronics across highways. Typically, big rigs can weigh up to 80,000 pounds when fully loaded. They are equipped with advanced features like GPS navigation, air brakes, and sometimes even autonomous driving technology. Their size and weight require special driving skills and licenses, making them a vital part of the economy.