Heavy duty trucking is the cats meow of trucking. These are big, big 18-wheel trucks designed to get whatever you want, whenever you want at the right cost. The truck itself is split into two areas or pieces. The first piece of the truck is called the tractor. The tractor is the front of the truck containing sleeping areas and the engine compartment. This is where the driver of these monstrous trucks may sleep eat and generally live for sometimes months at a time. The second piece of the heavy duty truck is the trailer. The trailer is designed to be packed with products being delivered all over the country. This is the main portion of the truck and where all the weight is distributed. A tractor usually weighs around 30,000 pounds. With a trailer added on, the combine weight usually reaches about 80,000 pounds. These are more modernly known as semi-trucks. In the 1920s, heavy duty trucks became popular. The Great Depression came and went leaving a meager picking of heavy duty truck manufacturers. Until the mid-90s, there were only about 9 companies left that manufactured heavy duty trucks.