Compartmentalisation in logistics planning and optimisation

In many logistics operations, a vehicle's capacity cannot be analysed as a single available space.

Some vehicles have several compartments, tanks, chambers, loading zones or internal divisions. Each of these areas may have a specific capacity, its own constraints and particular conditions of use.

This is known as compartmentalisation.

Compartmentalisation is especially important in sectors such as fuel distribution, gases, food, chemicals, temperature-controlled transport and the movement of incompatible goods.

In these cases, planning a route is not just about knowing whether the vehicle has enough capacity. It is also necessary to decide which product goes into each compartment, which orders can be combined and how that distribution affects the final route.

What is logistics compartmentalisation?

Compartmentalisation means dividing a vehicle's capacity into several independent units.

For example, a tanker may have several compartments for carrying different products or delivering different quantities to several customers. A refrigerated vehicle may have zones at different temperatures. A lorry may be divided into separate spaces for incompatible goods or goods with specific requirements.

Each compartment may have a maximum capacity and, in some cases, a recommended minimum capacity.

This means it is not enough to say that a vehicle can carry 20,000 litres, 10 tonnes or 30 pallets. It is necessary to know how that capacity is distributed internally.

A vehicle may have sufficient total capacity and still be unsuitable for a particular combination of orders.

Why it complicates planning

Compartmentalisation adds another layer of complexity to logistics planning.

In a simple plan, the system assigns orders to vehicles based on total capacity. If a vehicle can carry 10,000 units and the orders total 8,000, the assignment appears valid.

But with compartments, the question changes.

It is not enough to know whether the load fits in the vehicle. It must fit correctly within its compartments.

• An order may require a specific compartment.
• Two products may not be mixed.
• A compartment may be only partially used.
• A quantity may not fit well into any available combination.
• The unloading sequence may determine how the load must be arranged.

This makes optimisation more difficult because order allocation depends not only on the vehicle, but also on its internal structure.

Total capacity versus usable capacity

One of the most common mistakes is confusing total capacity with usable capacity.

A vehicle may have a high total capacity but be unable to use all of it for a particular operation.

For example, if a tanker has several fixed compartments, the available orders may not fit the capacity of each compartment exactly. The vehicle may leave with spare capacity even though, in theory, there is still room.

The same can happen with products that cannot be mixed, different temperature requirements or goods that require physical separation.

In these cases, optimisation must find the best possible combination of orders, products, compartments and routes.

Efficiency does not depend only on filling the vehicle, but on filling it correctly.

Product compatibility

Compartmentalisation is often closely linked to product compatibility.

Some products can travel together without difficulty. Others require separation. Some need temperature control. Others cannot share space because of regulations, safety, quality or commercial conditions.

For example, in fuel distribution, a compartmentalised tanker can carry different products, but each product must be assigned correctly to a compartment. In food distribution, some products may require chilled, frozen or ambient conditions. In chemical transport, compatibility can be even more critical.

These rules must form part of the planning process.

If they are not taken into account, the result may be a route that cannot be loaded or a prohibited combination of orders.

Compartments and orders

In a compartmentalised operation, an order may occupy one or more compartments.

Several compatible orders may also share the same type of space, or a compartment may be reserved for a particular product.

This means several decisions must be solved at the same time:

• Which orders are assigned to each vehicle.
• Which product goes into each compartment.
• What quantities are loaded into each division.
• Which combinations are compatible.
• Which route allows the load to be unloaded correctly.

Order allocation and compartment allocation are interrelated. A poor loading decision can make an apparently good route unfeasible.

Unloading sequence

Compartmentalisation can also affect the unloading sequence.

In some operations, the order in which customers are visited may depend on how the load is arranged. If the goods are not accessible at the right time, this can cause idle time, unnecessary handling or even make delivery impossible.

In tanker operations, for example, planning must consider quantities, products, customers and compartments. In other types of transport, the physical placement of goods may determine the sequence of stops.

For this reason, optimisation cannot completely separate the route from the load.

Good planning must coordinate both.

Compartment utilisation

One common objective is to improve compartment utilisation.

The aim is not necessarily to fill every compartment to its maximum, but to find an efficient and feasible combination.

Sometimes it may be preferable to leave some free space if this helps meet schedules, avoid incompatibilities or reduce mileage. In other cases, it may be more profitable to wait and group certain orders so that a compartmentalised vehicle can be used more effectively.

The decision depends on many factors:

• Capacity of each compartment.
• Type of product.
• Order volume or quantity.
• Customer locations.
• Time windows.
• Vehicle cost.
• Fleet availability.
• Delivery priority.

Optimisation must assess these variables together.

Compartmentalisation and logistics cost

Compartmentalisation has a direct impact on logistics cost.

Poor allocation can lead to underused vehicles, more routes than necessary, additional mileage or difficulties during loading and unloading.

It may also force the use of more expensive vehicles when better planning would allow the operation to be completed with more suitable resources.

By contrast, good compartment management can improve fleet utilisation, reduce travel and prevent unfeasible routes.

Cost depends not only on distance travelled, but also on how the available capacity is used.

Why manual planning is not enough

Compartmentalisation can be difficult to manage manually.

When there are only a few orders and vehicles, an experienced person may find a reasonable solution. But as the number of orders, products, compartments, constraints and time windows increases, the number of possible combinations grows rapidly.

The planner must consider load, product, vehicle, route, schedule and cost at the same time.

This makes it easy to overlook better alternatives or build routes that later require manual adjustments.

Optimisation software can analyse many combinations and identify allocations that are not obvious at first glance.

Route optimisation with compartments

Route optimisation with compartmentalisation must solve the problem in an integrated way.

It is not enough to optimise routes first and then try to fit the load. Nor is it enough to fill vehicles and then sequence the deliveries.

Both decisions must be coordinated.

The system must assess whether orders fit into the available compartments, whether products are compatible, whether the unloading sequence is feasible, whether schedules are met and whether the total cost of the plan is appropriate.

This approach makes it possible to build more realistic routes and reduce incidents during execution.

Benefits of considering compartmentalisation

Including compartmentalisation in planning delivers important benefits:

• Better utilisation of compartmentalised vehicles.
• Fewer unfeasible routes.
• Fewer loading errors.
• Better allocation of products and orders.
• Fewer unnecessary miles.
• Greater control over compatibility constraints.
• More realistic plans.
• Lower operating costs.

In sectors where compartmentalisation is critical, ignoring it can turn an apparently good plan into a solution that cannot be executed.

Conclusion

Compartmentalisation is a key factor in many transport and distribution operations.

When vehicles have tanks, chambers, zones or internal divisions, total capacity is no longer enough for correct planning. It is necessary to know what fits into each compartment, which products are compatible, which orders can be combined and how all of this affects the route.

Good logistics optimisation must integrate loads, compartments, constraints, schedules and journeys into a single plan.

In operations where compartmentalisation determines loading and delivery, LOGISPLAN applies Evolution Algorithms' experience in logistics optimisation to build feasible, efficient routes adapted to the actual structure of each vehicle.