[hackermom]

Reading this got me thinking about the sound signal schemes that traffic stop devices - sometimes the lights, sometimes the push button boxes - emit to aid those with visual impairment.

The Swedish system is a mechanical ticker placed inside the push button box, like a very loud clock that ticks slowly at one tick about every other second during red/yellow, and then picks up pace to about 7-8 ticks per second during green, cleverly aimed towards the listeners' intuition, telling them to "slow down" and "hurry across". I remember how this even served a good purpose and reminder for me as a kid, when I was too young, too impatient and too reckless to pay attention to the streeth lights - but the loud and clear sound signal and its intuitive meaning never escaped my attention.

What's used where you live?

[jevinskie]

My university (Purdue, USA) has an audio countdown with a seconds tick.

[eru]

You can also hear those ticks in parts of Germany.