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Archive for January 9th, 2013

Traffic Signals: Green LED Failures

Traffic Signal - dead green LEDs - 2012

Traffic Signal – dead green LEDs – 2012

In our (admittedly limited) travels around New York State during the last half decade or so, I’ve seen many (as in, dozens of) traffic signals with this failure:

Apparently the topmost LED string burns out first, leaving the other two (?) strings intact. The earliest picture I have dates back to 2008, so this is a problem of long standing that’s probably wiped out any projected maintenance cost reduction for the entire purchase. The most recent failure I spotted, a few weeks after taking this picture, has a flickering upper string that means it’s not long for this world.

Somewhere up around Albany, I recently saw a green signal with only that string lit up and the other two (?) strings dead, but that’s the sole exception to the pattern.

Of late, NYS DOT has been installing a different green lamp with the LEDs in each string scattered over the entire surface and no diffuser. That means a failed string, of which I’ve already seen several examples in the area, darkens a few spots without being particularly obvious; a less common failure has a few flickering “pixels” that will eventually go dark. While that’s a net win, I wonder why only green lamps have this problem: we very rarely see red or amber lamps with any failed LEDs.

One red LED lamp down the road did fail spectacularly: the whole thing flashed, slowly and somewhat irregularly. Not a flicker, but a flash: long off and short on.

It’s hard to get pictures of failed traffic signals…

While I suppose I should report them, previous attempts to do so have only led to requests for the ID number of the traffic control box, which generally can’t be seen from the traffic lane. I am not stopping at an intersection, getting out, finding the box (perhaps crossing the intersection to get there), finding the ID number, and taking a picture for later reference; you know what happens to people who take pictures of infrastructure. You’d think the signals could phone home on their own, but they’re likely not connected.

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