A semi-truck, also known as a tractor-trailer or big rig, is a large vehicle used for transporting goods over long distances. It consists of two main parts: the tractor, which is the front section that contains the engine and driver's cab, and the trailer, which is the rear section that carries the cargo. Semi-trucks are essential for the freight transportation industry, moving a significant portion of goods across highways. These vehicles are designed to be powerful and efficient, often equipped with advanced technology for safety and navigation. Semi-trucks can vary in size and configuration, but they typically have multiple axles to support heavy loads. They play a crucial role in the economy by ensuring that products reach stores and consumers in a timely manner.