Another driver's card in the tachograph: CJEU says a fixed, very high fine must be reducible, but short use does not count

The Court of Justice of the European Union has ruled that a country cannot impose a very high, entirely fixed fine on a driver who used another person’s driver card: there must be a way to reduce it according to the specific case. But the same judgment shuts the door on one of the most common defence arguments: having used the card for only a short time does not count.

The judgment in Case C-437/25 is dated 17 September 2026. It only reached the trade press this week.

The case

On 26 July 2024, a Bulgarian driver inserted into the tachograph a driver card belonging to someone else. Bulgarian law sets a fixed fine for this infringement of 1,500 leva, about €767, which neither the authority nor the court can reduce. The Administrative Court of Gabrovo asked the Court of Justice whether this is compatible with EU law.

The Court noted that the amount is higher than the average Bulgarian wage and that those who pay it are mostly lorry drivers (paragraph 39 of the judgment).

What the Court decided

1. A very high, rigid fine is not proportionate. Article 41 of Regulation (EU) No 165/2014 requires Member States to have “effective, proportionate and dissuasive” penalties. A very high fine, with no possibility of reducing it according to the circumstances of the case, breaches that principle (paragraphs 41, 42 and 48).

2. Length of use is not a mitigating factor. Using another person’s card is among the most serious infringements, regardless of duration (paragraph 43). Unlike exceeding driving time, where seriousness increases with the excess, here enforcement becomes impossible from the first minute (paragraph 46). So having used the card for “a very limited period” cannot reduce the fine (paragraph 44).

3. Proven negligence can mitigate. Among the circumstances that can reduce the fine is the driver being able to prove that they used someone else’s card through negligence, and not on purpose (paragraph 47).

What this changes for drivers

• The Court’s interpretation applies in all Member States. Anyone fined, in any EU country, with a fixed, very high fine that the law does not allow to be reduced can rely on this judgment to challenge it.
• The judgment does not make the infringement any lighter. It is still one of the most serious under the regulation, and the fine can still be high, as long as it can be adjusted to the case.
• “It was only a few kilometres” is not a defence.
• A mistake, for example cards swapped in a two-driver crew, can count as a mitigating factor, but only if it is proven. Anyone who notices such a mistake should record it straight away, in writing and with the tachograph printout, and inform the company. Without proof, the argument does not hold.

For the general rules on cards and software updates, see also tachographs: software updates are now mandatory.