Transfer dump trucks are specialized vehicles designed for transporting bulk materials. They consist of a standard dump truck with an additional trailer that can carry extra loads. This setup allows for efficient hauling of larger quantities of materials, such as gravel, sand, or construction debris, making them ideal for construction sites and roadwork. The unique feature of transfer dump trucks is their ability to unload materials from both the truck and the trailer. This dual unloading capability enhances productivity, as it allows operators to quickly and easily deposit materials in multiple locations without needing to make extra trips.