Admissibility of zero-tolerance rule for THC in road traffic and affirmation of conditional intent in cannabis consumption

Facts

The complainant A. was stopped by police at 01:50 on 20 June 2018 during a traffic check on the A1 motorway in the canton of Aargau. During the check, police officers observed physical signs such as slight swaying and reddened conjunctivae. A blood and urine test ordered at the time showed a THC level of 4.4 µg/L (confidence interval: 3.0 µg/L to 5.8 µg/L).

The public prosecutor’s office in Baden issued a penal order against A. on 8 August 2018 for the offence of intentionally driving while unfit to drive due to cannabis consumption under Art. 91 para. 2 lit. b RTA in conjunction with Art. 31 para. 2 RTA and Art. 2 TRegO. The District Court of Baden convicted A. by judgment of 24 October 2019 to a suspended fine of 30 daily rates of CHF 50 each and a fine of CHF 300. On appeal, the Higher Court of the canton of Aargau upheld this conviction by judgment of 19 January 2021.

A. filed an appeal in criminal matters with the Federal Supreme Court on 17 May 2021, seeking the quashing of the judgment and an acquittal on the charge of driving while unfit to drive. In the alternative, he requested that the matter be remitted to the lower court for reassessment. The Federal Supreme Court did not enter into the appeal and dismissed it.

Considerations

3.1 The complainant argued that the lower court had affirmed unfitness to drive solely on the basis of exceeding the THC threshold of 1.5 µg/L without this value allowing any conclusions to be drawn about the actual effect of the substance. He contended that the conviction violated the principle of legality (Art. 1 SCC), the principle of certainty, the presumption of innocence (Art. 10 CrimPC), the principle of investigation (Art. 6 para. 2 CrimPC), the principle of proportionality (Art. 5 para. 2 Cst.), the prohibition of arbitrariness (Art. 9 Cst.), and the right to a fair trial (Art. 29 para. 1 Cst. and Art. 3 para. 2 lit. c CrimPC). He further claimed that his right to be heard (Art. 29 para. 2 Cst.) had been violated.

3.2 The Federal Supreme Court examined the delegated power of the Federal Council and the Federal Roads Office (FEDRO) under Art. 55 para. 7 lit. a RTA. The zero-tolerance rule for THC laid down in Art. 2 para. 2 TRegO and the determination limit of 1.5 µg/L THC in blood set in Art. 34 lit. a RTCO-FEDRO had been issued within the scope of the delegated powers. These threshold values were to be classified as determination limits enabling reliable quantitative determination of a substance in a sample, but not as effect limits indicating a specific impairment of driving ability. The distinction between determination and effect limits is recognised in case law (Judgment 6B_136/2010 of 2 July 2010).

3.3 The complainant criticised the Federal Council for exceeding its powers by setting determination limits instead of effect limits. The Federal Supreme Court held that it could only review the Federal Council’s exercise of discretion for obvious overstepping of delegated powers or arbitrariness (Art. 190 Cst.). The regulation was not arbitrary, as there were no reliable scientific data on the relationship between THC concentration and unfitness to drive. The zero-tolerance rule was historically justified by the Federal Council’s dispatch of 31 March 1999, which explicitly mentioned the possibility of zero limits for certain substances. The regulation was therefore not untenable.

3.4 The Federal Supreme Court confirmed that the assessment of unfitness to drive under Art. 91 para. 2 lit. b RTA could be based on the said regulatory provisions. The alleged violations of law did not exist. The conviction also did not violate the principle of legality in criminal law, as Art. 55 para. 7 lit. a RTA expressly reserved the regulatory provisions. There was no room for any judicial assessment beyond the proof of the THC concentration.

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