This is material to supplement Warehouse & Distribution Science, a textbook and a graduate course taught at the Georgia Institute of Technology by John J. BARTHOLDI, III and Steven T. HACKMAN. Everyone is welcome to use the book and materials here for educational purposes, so long as the copyrights remain intact. You will find more information and technical details on these topics within the book.

Consolidated Freightways

Consolidated Freightway, also known as CF, went out of business in 2002. They were a trucking company that competed in the "less-than-truckload" (LTL) market, which means that typical shipments are too small to fill the trailers. The challenge in delivering such freight is to do it both quickly and efficiently. Frieght can be delivered quickly by sending it directly to its destination; but this would be terribly inefficient because most trailers would be nearly empty.

The LTL carriers try to improve freight density by organizing the flow into a hub and spoke network. Most shipments are carried to large regional crossdocks that are "hubs" at which freight is consolidated so that it joins other freight going in the same direction. Thus a typical shipment will travel as follows: From the origin to the local satellite terminal, where it is transferred to a trailer along the spoke to the hub crossdock. It will be transferred to another trailer, where it will join freight traveling together to a destination hub, where it will be tranferred to another trailer traveling along a spoke to the destination terminal. Finally, it will be transferred to a local truck for delivery to the destination.

The LTL carriers, such as Yellow Transport or Roadway or American Freightways, that serve much of North America, typically have 400-500 terminals and 20-30 hubs. Both satellite terminals and hubs are crossdocks, but the hubs are where the highest volumes of freight pass.

Within the crossdock the main concern is to move freight quickly out of its arriving trailer and pack it tightly into its departing trailer. It is important that each trailer be packed full and tight. First, this prevents shifting of freight and possible damage. Second, this increases utilization of the trucks, trailers, and drivers. However, this is quite difficult in LTL because, unlike the parcel delivery market, the freight is of higly variable size and weight.

Click on any image to enlarge it.
LTL crossdock Like many LTL crossdocks, this one is a narrow rectangle surrounded by doors at which trailers are parked to exchange freight.
LTL tractor It may look like a truck but it is called a tractor. Typically a tractor pulls two 28-foot long trailers, called "pups".
View down the length of the crossdock Again this is typical of the industry: Freight has been docked in the center of the floor, while forklift trucks drive along the walls to carry freight to the appropriate departing trailers.
A tight packing of freight in a trailer To make the trip efficient, the trailer must be filled as completely as possible. This one has been packed tightly so far.
A bad packing of a trailer This is a badly-packed trailer. It looks like the loader was having trouble fitting the freight together tightly and so stacked some cargo in an unstable way. This freight could shift in transit and cause damage.

Sometimes freight simply cannot be stacked with both high density and stability. To a large degree the quality of packing is determined by the cargo itself: Some things are hard to pack because they do not fit well together. This is made worse by the fact that the freight arrives as in a game of Tetris: The loader can never tell what will arrive next. He can defer packing freight by "docking" it temporarily, but there is limited space to do this and, anyway, this requires an additional touch of the cargo. Also, the freight cannot be held out long because it must keep to shipping schedule.

Loose freight in a trailer In fighting for business survival, CF made a business decision which seemed reasonable at the time but which ultimately hurt them. This was to get new business by lowering rates and accepting some unusually hard-to-handle freight. You can see the result in this trailer, where almost all the freight is loose and so has to be handled individually, incurring larger labor costs.
Unloading a trailer and building pallets of freight Another problem arose from the emphasis placed by CF on filling trailers as completely as possible. To achieve tighter packs, the workers de-palletized some freight because the smaller pieces fit better. Unfortunately, this creates extra work, both in the origin terminal (to de-palletize) and, especially, in the destination terminal (to re-palletize).
Example of freight that is hard to pack This item takes up a huge amount of space for its weight -- and LTL pricing depends most strongly on weight.
Example of freight that is hard to pack This item is heavy and so should be loaded low; but it create instabilities if anything was stacked atop it. It will probably render the space above it unusable.
Spray-painted sign on the back of a trailer This shows some of the challenges facing LTL. Because of the the North American Free Trade Act (NAFTA), the US, Canada, and Mexico are exchanging trailers more freely. However, traffic laws are not consistent. This US-based trailer did not have the caution signs required in Mexico, so an enterprising driver provided them.

Copyright © John J. BARTHOLDI, III. All Rights Reserved. This is material to supplement the textbook Warehouse & Distribution Science.

Last revised: 27 September 2003