In Boston there was a system: when one is biking or rollerskating or running or just generally ending up in a situation where one has to pass some pedestrians walking along, you could yell “On your left!” or “On your right!” and people immediately understood, without looking back, what was going on: somebody or something faster than you was just about to pass you from either your left or right side, so better not step there. Of course it always came out more like a one-word “onurleft” but people understood it perfectly anyway.
The system worked beautifully.
Alas, there is no such custom in Finland. Try doing this in Finland by yelling “Vasemmalla puolellasi!” or something similarly akward. Not only are the words too long, but if by some miracle you manage to yell them before you’ve passed the people, what you might get as a reaction are a couple of facial expressions representing bafflement, disorientation or a general “WTF?!”-kind of an attitude. And, most likely, the person in front will jump right under you or perform some other kind of a bad move.
When biking, you have the bell you can ring – but this only causes the people ahead of you to either glance behind them to see what’s happening or to randomly jump around the road. Neither practise does the person desiring to pass these people any good, nor, I would argue, for the one being overtaken. Plus when rollerskating or running, you don’t have a bell.
How could we get this kind of a convenient system to work in Finland?