Drive-in pallet rack is a very common material handling storage solution for high-volume SKUs. It’s highly condensed footprint with depth typically 6-8 (up to 10) pallets deep and several levels high… these systems can really pack in the pallets. The design is relatively simple too, without moving or dynamic parts like other dense storage solutions (namely push-back and pallet flow rack).
Pallets are placed on static parallel rails instead of carts and wheels or rollers. Pallets remain stationary until removed by the forklift. However because the forklift has to enter the actual rack system for loading and unloading, drivers must be highly trained and forklift/rack interaction rates are high. Also systems usually require an extra measure of pallet rack safety guards to protect the system integrity against forklift strikes.