[QUOTE=awk.pine]
Er. Here’s my $0.02.
Sodium vapor lamps are highly efficient … during operation. However, starting the lamp takes a fair amount of power. It takes far more current to cause the arc in the first place than to maintain it. Therefore, street lights turn on consecutively rather than concurrently in order to avoid causing massive dips in the power grid at dusk. Furthermore, street lamps next to each other are installed at the same time, are used the same amount, and so age at the same rate.
Conclusion: when all the lamps on a street are old enough to overheat, they will overheat in a pattern. Just as lamp A turns on, then lamp B, then lamp C, lamp A will overheat and turn off, then B, then C. The timing may coincide roughly with how long it takes to walk from one lamp to another.
Of course, this is an armchair hypothesis. I know less about sodium vapor lamps than wikipedia. But it explains the phenomena to my satisfaction.
[/QUOTE]
Not a bad hypothesis, but I’m not sure whether such switching schemes are actually widely implemented, if at all.
One thing that is true though, is that when sodium vapour lamps start to fail, they often start turning on and off repeatedly - the heat causes them to fail, but when they cool down, they’re sufficiently operational to start up again, then they heat up and fail again.
There are a number of lamps like this on the high street of the village where I live - the odd thing is that when I first noticed one, my initial thought was “I’ve seen that lamp turn off before - must be something wrong with it”. It seems rather hubristic to be thinking “That lamp turned off, and I’m here, so I must be magic!”.
My question for the folks who claim they have this ability is: What do you notice the lamps doing when you’re not there?