Line Haul in Logistics: How the Trunk Leg Works

In freight transport, line haul is the long-distance leg that moves goods between two fixed points: a depot and a sorting hub, a factory and a port, two terminals in the same network. It is the trunk of the journey. The local collection at one end and the local delivery at the other are separate legs, run with different vehicles and costed differently.

The defining feature is that a line haul runs to a timetable rather than to a single order. Departure and arrival times are set in advance, the vehicle goes whether or not a particular consignment made the cut-off, and everything downstream is built on those times holding.

Where the trunk leg sits in the journey

Freight is collected locally and brought into a depot, where it is consolidated into bigger units and loaded for the long leg. The line haul vehicle runs to the receiving hub or depot, and there the load is broken down and re-sorted by destination for local delivery.

That is why the trunk leg is usually run as full truckloads between sites even when the individual consignments on board are small. The purpose is to move as much as possible in one movement, so the cost of the distance is shared across everything in the trailer.

Why the timetable matters more than any single load

A line haul departure has a cut-off. Freight that reaches the depot after the cut-off waits for the next run, which is a whole cycle later. So dispatchers plan backwards from the cut-off: the collection rounds have to be back, the paperwork done and the trailer loaded in time for the driver to leave on the slot.

The arrival end works the same way in reverse. The receiving site has planned its sort and its delivery rounds around the scheduled arrival, so a late trunk leg does not delay one shipment. It pushes a whole shift of local deliveries into the next day.

What the trunk leg actually costs

The cost of a line haul sits mostly in distance, in driver time and in what the road itself charges. Fuel burns with the kilometres, tolls are charged per country, and the driver is paid for the hours.

Because so much of that cost is attached to the movement rather than the contents, fill is what decides the cost per pallet. The tolls and the driver hours do not move with the payload: both are charged against the vehicle and the time, not the load. Fuel does move with the weight, but not by enough to make a light trunk leg a cheap one, so a trunk service lives or dies on how well the network feeds it.

It is also why the return leg gets so much attention. A vehicle that runs back loaded earns on both directions of one trip, so dispatchers look for a backhaul rather than accept empty running home.

Line haul and the last mile

The trunk leg is long, scheduled and high volume. The last mile is short, variable and full of stops, run with whatever fits the street and the dock at the far end.

Confusing the two is expensive both ways: a trunk vehicle sent onto a city round wastes its capacity and meets access restrictions, while small vehicles on the trunk make you pay for the distance several times over.

What a dispatcher watches on a line haul

The departure, first. Then the driving and rest time the leg needs, because the plan has to fit the hours the driver has left and not only the distance on the map. A leg that looks comfortable in kilometres can be impossible on the clock.

Then the arrival, measured against the sort at the receiving site rather than the customer. An arrival early enough to make the sort is on time. One that misses it by minutes has effectively lost a day, however good the transit time looked.

And the handover. A trunk leg often ends in a trailer swap rather than a full unload, so the handover is recorded on the consignment note, with any reservations about the load written on it there and then.

The same word in other modes

Air and ocean freight borrow the term for the same idea: the port-to-port or airport-to-airport movement is the line haul, with road collection and delivery legs either side. The scheduled, fixed point character carries across modes, not the vehicle.

So when a customer says the line haul is covered, ask which leg they mean and where their responsibility stops. On a door-to-door job, a booked trunk says nothing about who collects at origin or who delivers at the far end, and that gap is usually where the argument about cost and delay starts.