How would you mark a bus that needs to be left standing at night on an Inter-urban road?

1. Same as any other vehicle.
2. Marking is not obligatory, but it must be immediately towed away from the place.
3. Correct answer: By placing a warning triangle seen by approaching vehicles from a distance of at least 100 meters, as well as by operating the distress flashers (double indicators).
4. By placing a warning triangle seen by approaching vehicles from a distance of at least 50 meters, accompanied by a flickering yellow light seen from a distance of 100 meters.

WhyA bus left at night on an inter-urban road is marked with a warning triangle visible from at least 100 m and the hazard lights on. 50 m is not enough.