Hub-and-spoke freight networks

Why a centre beats a web of direct links

Connecting many locations directly requires a link for every pair of locations, and the number of pairs climbs steeply as locations are added. Each of those links would carry only the freight destined for one place, so most vehicles would run part empty. Route everything through one centre instead and each location needs a single inbound and outbound connection, which fills far larger vehicles on far fewer journeys. The saving comes from vehicle fill and driver productivity, not from distance. A network accepts extra kilometres in order to remove empty capacity, and it wins whenever the freight per pair of locations is small.

The sortation window is the network's heartbeat

Everything arrives at the hub within a compressed period, is separated by destination, and departs again shortly afterwards. Doors are assigned by destination, freight is scanned as it crosses the floor, and the whole exercise is timed so the outbound vehicles can reach delivery areas for the start of the next working day. Nothing about this can be extended for late freight without delaying every vehicle in the building.

What an individual consignment pays for the design

Three things. Extra distance, because the routeing is indirect. Extra handling, because the goods are unloaded and reloaded at least once more than they would be on a direct run. Extra rigidity, because collection cut-offs are set by the hub timetable rather than by what would suit the shipper. In return, the consignment gets access to a national or continental delivery map at a fraction of what a dedicated vehicle would cost.

Regional sorts, secondary hubs and bypass lanes

Large networks rarely run a single centre. Regional sorts handle traffic between neighbouring areas so it never touches the main hub, and secondary hubs absorb peak volume. Where two depots exchange enough freight to fill a vehicle between them, operators run a bypass trunk that skips the hub completely, which shortens transit and relieves the sortation floor at the same time.

Knowing when to leave the network behind

The hub earns its detour only while consignments are small relative to a vehicle. Once a shipper regularly despatches enough to fill one, direct running removes the handling and the cut-offs together. Sensitive cargo makes that decision sooner, because a sortation floor is a place where things get dropped, mis-scanned and separated from their paperwork.

Frequently asked questions

Does routeing through a hub always make transit longer?

In elapsed time, usually yes, because the freight waits for a scheduled sort. In practical terms it is often quicker than the alternative, since a direct vehicle would only depart once enough freight existed to justify sending it.

Why are collection cut-offs earlier than shippers expect?

Because the cut-off is set backwards from the sortation window, not from the delivery date. The collection vehicle must reach the depot, the depot must load its trunk, and the trunk must reach the hub before sorting starts.