Missing mileage is one of the most common compliance issues flagged by the DVSA during operator checks—and it can have serious consequences for your O Licence if left unresolved. In this guide, we’ll explain what missing mileage actually means, what causes it, how to investigate it, and how automated systems like TachoMagic can help reduce it across your fleet.
What Is Missing Mileage?
Missing mileage refers to any distance that a vehicle has travelled and the vehicle tachograph unit recorded it as a distance travelled with no driver tachograph card being used.
This means the vehicle moved, the tachograph captured the distance, but no driver card was inserted at the time. It’s a clear data gap - and a potential red flag for compliance.
Common Causes of Missing Mileage
Unexplained mileage can occur for many reasons, and not all of them point to wrongdoing. Here are some of the most common:
1. Driving Without a Card Inserted
If a driver forgets to insert their card, or deliberately removes it during driving, there will be a gap in the data.
2. Vehicle Moved by Someone Without a Card
Vehicles being moved in yards, workshops, or test centres by unauthorised staff can also generate mileage that isn’t captured on a driver card.
3. Tachograph Faults or Configuration Errors
A misconfigured or faulty tachograph can fail to record journeys correctly.
4. Driver Behaviour
In rare cases, drivers may attempt to avoid rest requirements or working time rules by tampering with data or intentionally removing their card.
How to Investigate Missing Mileage
The best and easiest way to be notified of missing mileage is by using tachograph analysis software (like TachoMagic). You will be notified in reports (often titled Missing Mileage Report, or Vehicle Without a Card Inserted), and it will tell you when it happened, and how much distance is missing.
Once you have established there has been missing mileage, it is important to find the root cause. From experience, we have found that the most common causes are:
- Someone quickly moving the vehicle in the yard.
- When vehicle is being tested for repairs or maintenance.
- Drivers genuinely forgetting to insert their driver card.
Taking Action for Missing Mileage
Once you’ve identified the cause of the missing mileage, respond accordingly. This might involve:
- Booking the vehicle in for maintenance if a fault is suspected
- Refreshing driver training to prevent repeat issues
- Taking formal action if there’s evidence of tampering or neglect
- Make a note of why the missing mileage occured. This may be needed later if questioned by any authority
How TachoMagic Can Help With Missing Mileage
Manual checks are time-consuming and often happen after the fact. That’s where TachoMagic comes in.
Our system automatically downloads and analyses tachograph data, helping you spot missing mileage as soon as it appears. Here’s how it helps:
Automatic Downloads
No need to chase drivers or visit vehicles—TachoMagic retrieves both driver card and vehicle unit data remotely. This allows you to see missing data instantly.
Infringement Reports
Get alerted to missing mileage and other issues before they become compliance risks. You can also schedule these reports to be sent to your inbox as often as required to make sure you're always kept up to date.
Live GPS & Geofencing
If a vehicle is moved while no card is inserted, TachoMagic’s tracking helps identify when and where it happened.
Make Notes
Our system allows you to leave notes on reports so you don't have to worry about remembering the reason in the future.
Tips to Prevent Missing Mileage
- Train Drivers Regularly: Make sure all drivers know the importance of inserting their card—even for short movements.
- Use Automated Downloads: Regular, automatic downloads mean issues are spotted early.
- Document Everything: If a vehicle is moved in a yard or garage, make a note of it.
- Monitor Infringements Weekly: Don’t leave it to a monthly report—by then, it could be too late.
- Keep Vehicles Well-Maintained: Tachograph faults can easily go unnoticed without a proper defect reporting system.
Final Thoughts
Missing mileage is one of those small issues that can quickly become a big problem. Whether it’s due to a driver error, workshop movement, or equipment fault, the key is catching it early - and documenting your response.
With tools like TachoMagic, you can automate downloads, receive early warnings, and spend less time chasing files or checking spreadsheets. If missing mileage has been a recurring issue in your operation, it might be time to rethink how you collect and manage your tachograph data.
