Is an adult passenger of a passenger car transported in the back seat obliged to use the seat belts?

Yes, the obligation to use seat belts applies to everyone in the vehicle, on both the front and rear seats. According to Art. 39 para. 1 of the Road Traffic Act, the driver and passengers must wear seat belts. This is crucial for the safety of all travellers, as during an accident, an unbelted rear-seat passenger poses a deadly threat to those in the front as well.