I'm an avid electric moped rider in Vienna, a moderately sized European city, and in my first few weeks of ridership, it was very clear that people just do not look if they don't first have an audio cue .. and indeed, I almost hit a number of people because they didn't hear me. Electric mopeds are smooth and near-silent - especially in the rush of a big city.

I've had days where all I can think of, is how to add sound to my moped in cool ways. #1 idea is to put a kind of buzzer/whistle on my helmet .. thought of the whole 'speed-based synthesiser app' that makes the "drrroooooot" sound (its a nonsense idea), but in the end, a plain old bell seems to be the most effective measure yet, in the effort to continue to enjoy the electric ride ..

I could imagine an industry standard 'speed synthesiser', though, but the jingle-bell is cute too, and cheaper ...