Cross-docking is a practice in logistics

Logistics

Logistics is the management of the flow of goods between the point of origin and the point of destination in order to meet the requirements of customers or corporations. Logistics involves the integration of information, transportation, inventory, warehousing, material handling, and packaging, and...

 of unloading materials from an incoming semi-trailer truck

Semi-trailer truck

A semi-trailer truck, also known as a semi, tractor-trailer, or articulated truck or articulated lorry, is an articulated vehicle consisting of a towing engine , and a semi-trailer A semi-trailer truck, also known as a semi, tractor-trailer, or (in the United Kingdom and Ireland) articulated truck...

 or railroad car

Railroad car

A railroad car or railway vehicle , also known as a bogie in Indian English, is a vehicle on a rail transport system that is used for the carrying of cargo or passengers. Cars can be coupled together into a train and hauled by one or more locomotives...

 and loading these materials directly into outbound trucks, trailers, or rail cars, with little or no storage in between. This may be done to change type of conveyance, to sort material intended for different destinations, or to combine material from different origins into transport vehicles (or containers) with the same, or similar destination.

Cross-Dock operations were first pioneered in the US trucking industry in the 1930s, and have been in continuous use in LTL (less than truckload) operations ever since.
The US Military began utilizing cross-dock operations in the 1950s.
Wal-Mart began utilizing cross-docking in the retail sector in the late 1980s.

In the LTL trucking industry, cross-docking is done by moving cargo from one transport vehicle directly into another, with minimal or no warehousing. In retail practice, cross-docking operations may utilize staging areas where inbound materials are sorted, consolidated, and stored until the outbound shipment is complete and ready to ship.

Advantages of Retail Cross-Docking

• Streamlines the supply chain from point of origin to point of sale
• Reduces handling costs, operating costs, and the storage of inventory
• Products get to the distributor and consequently to the customer faster
• Reduces, or eliminates warehousing costs
• May increase available retail sales space.

Disadvantages of Cross-Docking

• Potential partners don't have necessary storage-capacities
• or an adequate transport fleet to operate Cross-Docking
• Need of adequate IT-System

Typical applications

• "Hub and spoke
  Spoke-hub distribution paradigm
  The hub-and-spoke distribution paradigm is a system of connections arranged like a chariot wheel, in which all traffic moves along spokes connected to the hub at the center...
  
  " arrangements, where materials are brought in to one central location and then sorted for delivery to a variety of destinations
• Consolidation arrangements, where a variety of smaller shipments are combined into one larger shipment for economy of transport
• Deconsolidation arrangements, where large shipments (e.g. railcar lots) are broken down into smaller lots for ease of delivery.

Retail cross-dock example:
Using the cross-dock technique, Wal-Mart was able to effectively leverage their logistical volume into a core strategic competency.

• Wal Mart operates an extensive satellite network of distribution centers serviced by company owned trucks
• Wal Mart’s satellite network sends point of sale (POS) data directly to 4,000 vendors.
• Each register is directly connected to a satellite system sending sales information to Wal Mart’s headquarters and distribution centers.

Factors influencing the use of retail crossdocks

• Cross-docking is dependent on continuous communication between suppliers, distribution centers, and all points of sale.
• Customer and supplier geography—particularly when a single corporate customer has many multiple branches or using points
• Freight costs for the commodities being transported
• Cost of inventory in transit
• Complexity of loads
• Handling methods
• Logistics software integration between supplier(s), vendor, and shipper
• Tracking of inventory in transit

Crossdock facility design

Cross-docks in practice are generally designed in an "I" configuration, which is an elongated rectangle. The goal in using this shape is to maximize the number of inbound and outbound doors that can be added to the facility while keeping the amount of floor space inside the facility to a minimum. In 2004, Bartholdi & Gue demonstrated that this shape is indeed ideal for facilities with 150 doors or less. For facilities with 150-200 doors a "T" shape is more cost effective. Finally, for facilities with 200 or more doors the cost minimizing shape will be an "X".