TF, 29.10.2025, 7B_1388/2024
Facts
A driver is stopped by the police and subjected to a breathalyzer test, which reveals a breath alcohol concentration of 0.41 mg/l. The threshold for aggravated drunk driving is set at 0.40 mg/l. Convicted in the first instance of aggravated drunk driving (Art. 91 para. 2 let. a Road Traffic Act), the defendant appealed. The cantonal criminal court upheld the appeal, considering that the ordinance of the Federal Roads Office (FEDRO) which excludes any safety margin on breathalyzer measurements (Art. 20 OOCCR-FEDRO) lacks a sufficient legal basis. It then applied a 7.5% safety margin, bringing the alcohol level below the aggravated threshold. Consequently, it acquitted the defendant of the aggravated offense and convicted him only of simple drunk driving (Art. 91 para. 1 let. a Road Traffic Act). The Public Prosecutor's Office appealed this decision to the Federal Supreme Court.
Law
The Federal Supreme Court examined the validity of Art. 20 of the FEDRO ordinance concerning the Ordinance on Road Traffic Control (OOCCR-FEDRO), which stipulates that no safety deduction is applied to the values displayed by breathalyzers. It recalled the chain of delegation of authority:
- The Road Traffic Act (RTA) empowers the Federal Council to issue regulations on the "use of breathalyzers" (Art. 55 para. 7 let. b RTA) and authorizes it to sub-delegate to FEDRO the task of "regulating the procedures" (Art. 106 para. 1 RTA).
- The Federal Council, in the Ordinance on Road Traffic Control (ORTC), explicitly tasked FEDRO with setting "the margins of error inherent in the devices and measurements" (Art. 9 para. 2 let. b ORTC).
- On this basis, FEDRO enacted Art. 20 OOCCR-FEDRO.
The Federal Supreme Court ruled that this delegation is legal. The concept of "use" of a measuring device necessarily includes the rules for interpreting its results, including the question of a safety margin. Furthermore, FEDRO's decision to provide for no deduction is not unsustainable. Indeed, the legislature (the Federal Assembly) has already incorporated a safety margin favorable to the defendant by setting the breath alcohol limits using a conversion factor that is advantageous compared to the blood alcohol level. Finally, the reliability of breathalyzers is guaranteed by strict controls (by the Federal Institute of Metrology - METAS), and the defendant retains the right to request a blood test for verification, which he waived in this case.
Application to the specific case
The Federal Supreme Court found that the cantonal criminal court violated federal law by refusing to apply Art. 20 OOCCR-FEDRO. There is a sufficient legal basis for FEDRO to enact such a rule. The decision to set the safety margin at zero is a choice that falls within FEDRO's competence and is not arbitrary, given the guarantees of the devices' reliability and the margin already included in the setting of legal thresholds. Consequently, the result of 0.41 mg/l measured by the breathalyzer must be accepted as is, without any deduction. As this level is above the 0.40 mg/l threshold, the offense of aggravated drunk driving is established.
Outcome
The Federal Supreme Court allowed the Public Prosecutor's appeal. It set aside the judgment of the cantonal criminal court and remanded the case for a new decision based on the 0.41 mg/l alcohol level, without applying a safety margin, and for a new ruling on the sentence and costs.
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