DDD files – what they are and why to archive them

What a DDD file is

DDD is the file format into which data is downloaded from a digital tachograph. The name comes from the `.ddd` extension, and in practice it covers two different data sources: a file from the driver card and a file from the vehicle unit (the tachograph in the vehicle itself).

Both types are digitally signed, so it can be verified that nobody has tampered with the contents. That is exactly what makes them usable as evidence during a check – unlike an ordinary spreadsheet, which anyone can rewrite.

What data a DDD file contains

The file from the driver card carries a record of one particular driver's activities: when they drove, when they performed other work, availability or rest, which vehicles they drove and whether events occurred such as a card being inserted while driving.

The file from the vehicle unit contains the view from the other side: who drove the vehicle, what the speed profiles were, the odometer reading, calibrations and what are known as events and faults – a power interruption or a tampering attempt, for instance.

Only both views together give the full picture. That is why both cards and units are downloaded, not just one of them.

How long they must be kept

This is where an inaccuracy often spreads. Regulation (EC) No 561/2006, Article 10(5), requires a transport undertaking to ensure that all data downloaded from the vehicle unit and from the driver card is kept for at least twelve months after it was recorded.

A period of two years is often quoted. The European regulation, however, sets 12 months as the minimum – a longer period may follow from national rules, from requirements during checks, or it is simply a provider's recommendation. If you come across a different figure somewhere, check whether it is a legal obligation or a recommendation.

The regulation also requires that, at the request of an inspecting officer, this data is accessible either directly or remotely at the premises of the undertaking. Having it on a memory stick in a drawer is therefore not enough.

Why archive longer than the minimum

Twelve months is a minimum, not an optimum. A check at the undertaking may concern a period that just crosses the boundary, and missing data is hard to argue around.

The second reason is employment law. DDD files are often the only precise evidence of when a driver was at the wheel – useful in disputes about overtime, in dealing with an accident or in a transport claim.

The third reason is operational: history can reveal recurring problems, for example regular overruns of driving time on one particular route, which is more a planning error than the driver's fault.

What happens if you do not have the files

If an undertaking cannot produce the downloaded data for the required period, that is a breach of the obligation under the regulation and is dealt with during a check. Penalties are set by each member state individually, so they differ between countries.

The practical impact tends to be even more unpleasant: without the data you cannot prove that the driver complied with the rules. In a dispute you are then up against the enforcement authority's record with no evidence of your own.

The risk does not concern large hauliers alone. From 1 July 2026 the system also takes in companies with vans over 2.5 tonnes in international transport, which until now have had no experience of archiving tachograph data.

How to make archiving easier

The foundation is order in the process: firmly set download intervals, one place where the files are stored, and a backup. The files must not be edited – the digital signature is their entire value.

Downloading can be done manually via a card reader with the downloaded file archived, or remotely, with the data taken from the unit automatically. A remote solution removes the most common cause of problems, which is a forgotten deadline.

One caution: GPS tracking does not replace DDD files. SaveTrack handles the mileage log, position and costs; the statutory record of driver activity is a matter for the tachograph and its data.