What is the legal status of carrying dangerous goods (Gefahrgut / ADR) on public passenger transport buses in Switzerland?

1. Dangerous goods are restricted by SDR/ADR and the operator's carriage rules; only applicable exemptions and permitted personal quantities may be carried, while prohibited items or quantities must be refused
2. Any retail-packaged dangerous good may be carried without quantity limits or operator restrictions
3. All dangerous goods are prohibited without exception, including every permitted personal-use quantity
4. The driver may accept an uncertain substance based only on a passenger's assurance that it is harmless