What it costs to run a tractor unit

Ask what a tractor unit costs and someone quotes the list price. That is the number that matters least. Over a first life of four or five years a European long-haul tractor will spend several times its purchase price on diesel, more again on the person driving it, and a sum that still surprises people on tolls. The purchase decision is worth making carefully, but what you are really buying is a position on the other cost lines.

The working unit is cost per kilometre, and the first job is to split it in two: costs that accrue per kilometre (fuel, AdBlue, tyres, tolls, wear-driven maintenance) and costs that accrue per day the vehicle exists (finance, depreciation, insurance, road tax, operator licence, workshop and office overhead, and most of the driver’s pay). The two piles respond to entirely different levers, and mixing them is how fleets end up chasing the wrong saving.

The denominator is capped by law

Every fixed cost is divided by annual kilometres, and annual kilometres are limited by driving-time law before they are limited by anything else. Regulation (EC) No 561/2006 allows nine hours of driving a day, extendable to ten twice a week, with a ceiling of 56 hours in a week and 90 hours in any two consecutive weeks, and a 45-minute break after four and a half hours at the latest.

Ninety hours a fortnight is 45 driving hours a week. At a door-to-door average of 70 km/h — generous once loading bays, urban approaches and traffic are counted — that is around 3,100 km a week, so a single-manned tractor working 46 weeks tops out near 145,000 km a year. Almost no fleet achieves it. The point is that the ceiling is legal, not mechanical: the truck could do far more.

This is why utilisation dominates the model. The same tractor carries the same finance and depreciation whether it runs 90,000 km or 140,000 km a year, so the fixed component of cost per kilometre falls by more than a third between those two figures. Double-manning, back-loading and trailer-swap operations exist to attack that denominator, and none of them is a specification choice.

Fuel, and the fact that it is now a certified number

Since 2019 every new heavy vehicle sold in the EU has carried a declared CO2 and fuel-consumption figure produced by VECTO under Regulation (EU) 2017/2400 — a simulation over defined mission profiles and payloads, fed with measured data for the engine, gearbox, axle, tyres and air drag. For the first time, two tractors from different manufacturers can be compared on the same basis.

Use it with two cautions. VECTO’s mission profiles are not your route, so the declared figure is for ranking vehicles, not for budgeting. And it is a whole-vehicle result: aerodynamics, axle ratio, tyre choice and gearbox software move it as much as the engine does. Mercedes credits the reprofiled ProCabin front of the Actros L with up to 3%; Scania claims up to 8% for the Super powertrain against its own previous 13-litre. Treat both as best cases, then note that one cent per kilometre over 600,000 km is €6,000 — which is why a percentage point is worth arguing about.

The price side is not in your control but the exposure is. The IRU put the EU average diesel pump price at €1.54 a litre in August 2025, roughly half of it tax, with excise duty averaging €0.45 and ranging from €0.33 to €0.63 a litre across member states. The same truck on the same job has a materially different fuel bill depending on where it fills, which is why routing and fuel-card strategy sit alongside vehicle choice rather than below it.

Tolls have become a specification decision

Germany is the clearest case because the rates are written into statute. Annex 1 to the Bundesfernstraßenmautgesetz sets four partial rates. For a vehicle over 18 t with four or more axles — an ordinary 40-tonne artic — infrastructure costs €0.155 per kilometre, noise €0.012, air pollution for a Euro VI engine €0.023, and CO2, for a vehicle in CO2 emission class 1, €0.158. That totals 34.8 cents a kilometre. For a class 5 vehicle the CO2 partial rate is zero.

Read that again: the CO2 component is larger than every element except the infrastructure charge, and it is the only one you can change by buying a different truck. On 120,000 German motorway kilometres, the CO2 component alone is €18,960 a year.

This is not a German peculiarity. Under the Eurovignette directive as amended in 2022, tolls and vignettes for heavy vehicles have had to vary by CO2 emissions since 2024, and from 2026 the external cost of air pollution must be built in as well. The IRU’s 2025 cost work found Austrian tolls running at €0.62 per kilometre against €0.46 for fuel — the toll now costs more than the diesel.

The CO2 emission class is derived from the vehicle’s certified VECTO result. A number that began as an environmental label is now a line in the profit and loss account, and it belongs on the specification sheet next to the engine rating.

The driver, and why the cab is a cost line

In Western Europe the driver is the largest or joint-largest cost, and unlike fuel it does not stop when the truck does. Waiting at a loading bay, running empty to reposition and sitting out a mandatory rest are all paid time producing no revenue. Anything that raises the loaded proportion of the working day beats almost anything you can do to the vehicle.

That is also the honest argument for cab specification. A flat-floor, full-height cab of the sort fitted to the DAF XG+ or the Volvo FH in its taller variants costs money and a little fuel, and it is defended on retention rather than on efficiency. If a driver vacancy costs you weeks of a tractor standing still, the cab is competing against the fixed-cost-per-kilometre line, and it usually wins that argument.

Tyres, maintenance and the number nobody budgets

Tyres are two costs at once: rolling resistance shows up in fuel, casing wear shows up in replacement. Axle configuration decides how much rubber you buy — a 6x2 carries more than a 4x2, which is part of why the third axle is liftable.

Maintenance is best handled as a policy question rather than a forecast. A repair-and-maintenance contract converts an unpredictable variable cost into a fixed monthly one; that is a risk and cash-flow decision, not a saving, and it should be priced as such.

Residual value is frequently the largest single line in a three-to-five-year model and the one operators guess at. It is set by the used market, not by you, and it responds to emission class, completeness of service history and how ordinary the specification is. An unusual axle configuration or a rare engine step is cheap to buy and slow to sell.

Putting it together

Build the model in cost per kilometre with fixed and variable separated, put your own utilisation into the denominator rather than a brochure figure, and price tolls corridor by corridor rather than as a national average. Then sanity-check it against a route you already run. If the model cannot reproduce a cost you already know, it will not predict one you do not.