What type of apparatus is characterized by having a large complement of ground ladders but no aerial device?

The type of apparatus characterized by having a large complement of ground ladders but no aerial device is a quad. A quad typically includes a combination of equipment, including ground ladders, medical supplies, and firefighting gear, which make it versatile for various situations, especially in urban environments where aerial devices may not be feasible due to height restrictions or accessing narrow streets. The quad serves as a bridge between engine companies, which primarily pump water, and ladder trucks, which are equipped with aerial devices.

Ground ladders are essential for accessing buildings, performing rescues, and fighting fires in multi-story structures, making them a critical component of fire operations. The distinction of not having an aerial device simplifies the design of the quad, focusing on the operational needs that require more ground support while still providing necessary tools for emergency response.

Other types of apparatus listed, such as engines and brush trucks, have different primary purposes. Engines are focused mainly on pumping water and carrying hose lines, while brush trucks are designed for off-road firefighting in wildland areas. SAR (Search and Rescue) vehicles are specialized for search and rescue operations and do not typically carry the same complement of ladders as a quad.