Are you obliged to indicate a break-down of a motor vehicle on the express road throughout the time the vehicle remains parked there?

Yes, stopping a broken-down vehicle on an expressway, like the one in the picture, must be signalled for the entire duration of the stop. According to Art. 50 para. 2 pt. 1 of the Road Traffic Act, the driver must switch on the hazard warning lights and place a warning triangle 100 m behind the vehicle. Continuous signalling is crucial to warn other drivers travelling at high speed well in advance.