I returned back to the bell from the horn. I noticed that when people hear the bicycle bell they realize that the bicycle is behind and behave properly.

But when they hear the horn blast they think that it is the sort of a truck behind and jump sideways, maiking it risky to pass them.

I also noticed that my horn does not work in frosty weather. Though my bell also does not work but in rain.

The whistle seems to be the good idea, because the police uses whistles. Maybe only for emergency situatiions, since it is illegal. Once I cycled in the dark in the yellow reflective vest, which resembled the one, which the traffice police uses. I noticed that the cars were slowing down everywhere, as soon as they saw the familiar yellow outline in the dark. Probably they thought that it was the policemen on the motorbike. But it felt good.