When must you wait at a level crossing?

Your answer is completely correct because you must wait at a level crossing in all three situations according to German traffic rules.

First, when a flashing red light is on, it signals an approaching train, so you must stop and wait until the light stops flashing.

Second, when the barriers are being lowered or already down, crossing is forbidden for safety reasons, as a train will pass shortly.

Third, a railway employee waving a white-red-white flag is a manual signal indicating a train is coming or crossing is unsafe, so you must also stop.

In all these cases, waiting ensures safety by preventing vehicles from being on the tracks when trains approach. Always observe these signals at level crossings to avoid accidents.