Drive-in rack, also known as drive-in pallet rack or drive-through rack, is a type of high-density storage system designed to maximize warehouse space utilization. It allows forklifts to enter the rack structure and drive directly into the storage lanes to deposit or retrieve pallets.

In a drive-in rack system, pallets are stored on rails or beams that run perpendicular to the forklift's direction of travel. The forklifts drive into the storage lanes, typically with a last-in, first-out (LIFO) storage method, where the last pallet stored is the first one to be retrieved. This is because the forklift needs to access the pallets at the front of the lane first before reaching the pallets located deeper within the lane.

Drive-in rack systems are suitable for storing large quantities of the same product SKUs (stock keeping units) with a low turnover rate. They are commonly used in industries such as food and beverage, cold storage, and manufacturing, where a high storage density is required and product selectivity is not a primary concern.

Types of Drive-In Rack:

1. Single Entry Drive-In Rack: In this type, forklifts can enter the storage lane from only one side. The pallets are placed on rails or beams on both sides of the lane, and the forklifts drive in and retrieve pallets from the same entry point.

2. Double Entry Drive-In Rack: This type allows forklifts to enter the storage lane from both sides. This allows for more flexibility in accessing pallets and can help improve efficiency in certain warehouse operations.

3. Drive-Through Rack: Also known as a drive-thru rack, this type of system allows forklifts to enter the storage lanes from both ends. This enables a first-in, first-out (FIFO) storage method, as pallets can be loaded from one end and retrieved from the opposite end. Drive-through racks are often used in situations where product rotation and expiration dates are critical.

4. Drive-In/Drive-Through Hybrid Rack: This type combines elements of both drive-in and drive-through rack systems. It allows forklifts to access the storage lanes from one side as in a drive-in rack, while also providing the option to enter the lanes from both sides as in a drive-through rack. This hybrid design offers increased flexibility in terms of pallet access and retrieval.

It's important to note that the choice of drive-in rack type depends on factors such as warehouse layout, product characteristics, inventory turnover, and operational requirements. Each type has its own advantages and considerations, and selecting the appropriate system should be based on a careful analysis of specific warehouse needs.