How to stop fuel theft from trucks.

Fuel is the largest cost a fleet can control — typically a quarter to a third of operating costs for a trucking operation. That makes small, repeated losses expensive. A truck that loses 20 litres a night, five nights a week, loses more than 5,000 litres a year.

The hard part is seeing it. Diesel leaves no trace, records are often on paper, and consumption genuinely varies with load, road and driver. A driver who siphons 30 litres can blame a hill climb or a heavy load, and without independent data nobody can prove otherwise.

How fuel goes missing from trucks

• Siphoning from parked trucks. Fuel is drawn out through the filler neck overnight — at lodges, in border queues or at roadside stops.
• Tank and line tampering. Loosened drain plugs, drilled-and-plugged tanks and tapped fuel lines. These leave a slow decline rather than one sudden drop.
• Receipt fraud and short fills. The receipt says 300 litres; 260 went into the tank. The difference is split with a pump attendant, or the receipt covers fuel that was never bought.
• Jerry cans on the company account. Fuel bought for the truck goes into containers instead.
• Detours to sell fuel. An unscheduled stop off the route where diesel is sold on — then extra kilometres to cover the gap.
• Waste that looks like theft. Long idling, speeding and poor routing burn fuel too. It isn't theft, but it hides inside the same consumption figure, so you need data that separates the two.

Nine controls that work, cheapest first

1. Lock the obvious access points

Locking fuel caps, anti-siphon screens in the filler neck and secured drain plugs are cheap and quick to fit, and they stop opportunistic theft. They won't stop a determined driver or fraud at the pump, so treat them as the first layer, not the answer.

2. Control where and how fuel is bought

Use a short list of approved stations and pay on account or by card, not cash. Set a limit per vehicle per fill. Fewer, trusted stations make every receipt easier to check. If you run your own depot or forecourt, measure the storage tank and every dispense too — forecourt control and automatic tank gauging close the gap on your own site.

3. Reconcile every refuel against the tank

This is the control that closes most gaps. For each fill, compare the litres on the receipt with the rise in the tank level at that time and place. A 40-litre gap on a 300-litre fill becomes a same-day conversation with the driver and the station, not a month-end mystery. Paper alone can't do this, because you have no independent record of what actually reached the tank.

4. Fit calibrated tank level sensors

A capacitive sensor in the tank, calibrated to that tank's shape, gives a continuous litre reading. Ampenet's fuel sensors read to ±1% of full scale and report every 30 seconds through the vehicle's GPS tracker. Every refuel and every drop is logged with time, place and litres, and a sharp fall with the ignition off is flagged as a probable drain while it is happening — not discovered later.

5. Geofence routes, stops and stations

Draw approved routes, depots, customer sites and fuel stations on the map. GPS fleet tracking then alerts you to unscheduled stops, route deviations and refuels outside approved stations. Combined with the fuel reading, a stop where the tank level falls is no longer a guess.

6. Tie every trip to a driver

Driver identification by RFID card or iButton links each trip, refuel and drain event to a named driver. Without it, a shared truck has nobody accountable. With it, you can compare drivers' litres per 100 km on comparable routes.

7. Benchmark consumption, not just events

Track litres per 100 km per vehicle, per route and per driver every month. Slow leaks, tapped lines and steady skimming rarely trigger a single alert, but they push a vehicle above its peers. Investigate the outliers, not the average. This is where fleet data becomes a decision tool rather than a pile of reports.

8. Put cameras where disputes happen

When a driver disputes an alert, video settles it. AI dashcams cover the road and the cab, and a camera that keeps watching with the engine off — such as the Sentinel S5 — covers the overnight stop where most siphoning happens.

9. Make alerts someone's job

A drain alert at 2 a.m. is worth nothing if it is read at 9 a.m. Decide who receives which alert, what they do and how fast. If you don't run a night shift, a managed monitoring centre can watch alerts around the clock and call the driver or the yard while it still matters.

When you find a loss

• Keep the evidence: the event log with time, GPS location and litres, the receipt, and any footage.
• Talk to the driver with the data in front of you. Many cases close here.
• Apply the same policy every time. Inconsistency is what encourages drivers to test the system.
• Check the station as well as the driver. Short fills often involve both.
• Fix the process, not just the person. A recurring pattern on one route or at one station usually needs a process change.

How to tell it's working

Track four numbers every month:

• Reconciliation gap — litres paid for minus litres recorded in the tanks. It should shrink toward zero.
• Litres per 100 km — per vehicle and per route, against the same period before.
• Drain and anomaly alerts — a spike after installation is normal; the count should fall as drivers learn the system works.
• Fuel cost per kilometre — the figure your finance team cares about.

Once sensors, alerts and reconciliation run together, Ampenet clients typically report fuel savings of 15–25%.

Where to start

If you can only do one thing this month, start reconciling receipts against tank levels on your highest-consumption trucks. It tells you how big the problem really is before you spend on anything else.