Traffic lights and yellow snow?
February 6, 2010 5:56 PM   Subscribe

Do yellow traffic lights get clogged with blowing snow?

I heard a news story that with the installation of LED traffic lights in snowy climates there is a new problem that blowing snow fills up the shroud around the lights completely obscuring them. The explanation is the old incandescent lights produced enough heat to melt the snow, but the LED's do not.

So my question is, to you northerners, do/did incandescent yellow traffic lights fill up with snow? Since they're on for such a short time it seems to me they might. But I live in the desert.
posted by huckit to Travel & Transportation (27 answers total)
 
/central Ontario

I've never seen it happen
posted by Mahogne at 6:01 PM on February 6, 2010


I have lived in the midwest for about 20 years. I have never noticed lights filled with snow. I've seen snow on TOP of lights or even below at the base.

My first question is whether this was on Fox News after some environmentally friendly lights were put in?

My second question is that whether the news knew that snow comes from up and goes down. Even in blizzard like windy conditions I've never really seen it hole up somewhere that it can't fall down.

If the news is right, and the light DID melt the snow that holes up on the lights...me, and the other northerners would have noticed prominent icicles pointing toward the ground...from the traffic lights. I've never seen that.
posted by hal_c_on at 6:02 PM on February 6, 2010


Oh yeah...chicago.
posted by hal_c_on at 6:02 PM on February 6, 2010


No Fox News.

Simple google search yields this: http://www.engadget.com/2009/12/17/led-traffic-lights-dont-melt-snow-do-cause-accidents/

Easy with the silly political angle to the OP's original question.
posted by dfriedman at 6:07 PM on February 6, 2010


A brief story from the Chicago Tribune on whether or not a snow-obstructed signal contributed to the death of a motorist. Includes a picture of the signal.
posted by SuperSquirrel at 6:11 PM on February 6, 2010 [2 favorites]


I don't think that a "snow covered light" contributed to that motorist's death. I think that the other motorist not following the law regarding inoperative lights is what contributed to her death. It's right there in every traffic manual in North America: If a traffic light appears to be inoperative (like you can't see the light because because there is a power failure, or the lenses are covered in snow), you must treat the controlled intersection as a 4 way stop.
posted by barc0001 at 6:19 PM on February 6, 2010 [2 favorites]


Best answer: Apologies - here's a link to the complete article, all on one page.
posted by SuperSquirrel at 6:22 PM on February 6, 2010


I saw a couple of teenagers trying to fill one up with snow today by throwing snow at it. They weren't making much progress.
posted by interplanetjanet at 6:24 PM on February 6, 2010


I've never seen it. (Connecticut; New York.)
posted by pemberkins at 6:50 PM on February 6, 2010


After looking at the picture, it looks like the shades around the lights are pretty close together. I could see how that could cause a problem regardless of how much heat is put out. We have plenty of LED lights here in Minnesota and I've never noticed them filled with snow.
posted by advicepig at 6:53 PM on February 6, 2010


Keep in mind that blowing snow is itself rather rare.
posted by smackfu at 6:54 PM on February 6, 2010


I live in the midwest and have never seen this happen.
posted by Lobster Garden at 6:55 PM on February 6, 2010


Blowing snow is not so rare here in Minneapolis.
posted by advicepig at 6:57 PM on February 6, 2010


Best answer: I saw a light signal in Madison, WI fill up with snow to the point that you pretty much couldn't see the light through it. I only saw it once, during the the worst snow storm I experienced in the 11 years I lived there. The lights that weren't facing the wind were fine. I think I may have taken a picture of it because I thought it was so bizarre, I'll see if I can find it and post a link.

Here is is. You could just see a little bit of the red part of the light. Everyone was using the lights for the crossroad to figure out if they could go or not (no one was driving very quickly that day - I think we ended up with over 2 feet of snow).
posted by ugf at 7:06 PM on February 6, 2010


Best answer: Here in South Dakota where we have blowing snow 90% of the time in winter, I never saw the old yellow lights fill with snow. I did, however, see the new LED ones fill with snow almost immediately after they were installed. Some poor guy was out there in a bucket truck in the blizzard, using a broom to clean them out. It looked precarious.

When snow is blowing, you'd be surprised the places it can get into.
posted by bristolcat at 7:19 PM on February 6, 2010


I live in NW Indiana and we just had an article in the paper last week about upgrading to LED lights. Apparently the snow only blows into the lights on rare occasions (they cited Minneapolis, which gets much more snow, only having this happen once or twice a winter) and there will be people hired to go around with long brooms to brush the snow off the lights.
posted by IndigoRain at 8:23 PM on February 6, 2010


Response by poster: It's possible that the heat from incandescent reds and greens conducts enough to the yellow that it melts snow. Also, if the yellow was blocked people probably wouldn't care much since you'd soon find out the light was turning red (and therefore not take cool pictures and write news stories).

For the record I'm a huge LED fan and I agree that the occasional inconvenience is worth the 80-90% energy savings. I'd be curious how often lights are non-operational due to incandescent bulbs burning out. But I suppose that is another question.
posted by huckit at 8:36 PM on February 6, 2010


Im pretty skeptical of some of the conclusions drawn in these articles. The heat output of an incandescent bulb isnt very high. The idea that its going to just melt all this snow quickly doesnt seem to ring true with me. Yes, its putting x amount of heat in there, but thats probably not enough heat to make a real difference quickly. Those traffic accidents probably would have still happened.

I live in the midwest and have seen traffic lights filled with snow before. Its pretty rare and this was years ago, well before the move to LED.
posted by damn dirty ape at 11:55 PM on February 6, 2010


I see blowing snow turn into some pretty fantastic snowdrifts. Crazy snowdrifts. Snow blown and heaped up in strange, gravity-defying ways. Narrow South Philly streets are like science projects about wind. And I've never seen more than a minimal amount of snow buildup in a traffic light.

I figure that the lights, being strung on overhead lines, get battered about by the wind enough to counteract the snowblower-drift effect.
posted by desuetude at 12:42 AM on February 7, 2010 [1 favorite]


Beg pardon, it was Milwaukee, not Minneapolis. And here's the article in my paper.
posted by IndigoRain at 12:54 AM on February 7, 2010


It would be a rare occurence. Snow storms with sticky snow blowing in a certain direction with an intensity to cover a traffic signal do happen but experienced drivers can figure out what is going on. Such an event could also cover a stop sign which obviously does not have a built-in heater. Does that mean we should mandate built-in heaters for stop signs?

As far as traffic-signal related accidents in colder climes this would be down at the bottom of the list. I have seen power outages more frequently cause signal problems. A power outage would affect incandescent and LED signals the same. Basically this is a non-issue for a snowy slow news day.
posted by JJ86 at 6:56 AM on February 7, 2010


Stop signs exist in only one functional state, unlike traffic signals, which have at least three (stop, go, and whatever yellow means to you) and possibly more, depending on the existence of turn arrows*, etc. Also, stop signs have a recognizable shape, so even if you can't read the lettering, you can understand the meaning of the sign.

Also, power outages would affect the entire intersection, so all drivers would be affected in the same way. When only one signal is obstructed, or one light in the signal is obstructed, there can be confusion.

*The article I linked to posits that part of the confusion with the snow-obstructed light was due to part of a green turn arrow being visible, which possibly led to the driver mistaking it for a full-on green.
posted by SuperSquirrel at 7:07 AM on February 7, 2010


Trust me SuperSquirrel, a power outage can lead to worse problems for a longer period of time than snow obscuring a signal. Drivers unsavvy enough to understand a snow-covered signal's implications are unsavvy enough to understand a dead signal or a flashing signal and even obscured signs. I've seen it happen plenty of times where some drivers will not even slow for a flashing signal. Redundant signals for each direction minimize the possibility of a complete obscuring of all signals.

Also understand that in a weather condition that is so severe that signals are obscured most drivers are either driving cautiously or they are staying home. OTOH a power outage more often than not happens at peak times usually due to a traffic accident. I work as an engineer in the snow belt city IndigoRain posted an article link to and have been in a traffic section for several years. I am familiar with the problems associated with signals on a day to day basis.
posted by JJ86 at 7:37 AM on February 7, 2010


Wasn't trying to argue. ::shrug::
posted by SuperSquirrel at 7:53 AM on February 7, 2010


This is a prime example, IMHO, of why roundabouts are superior in nearly every way to traffic lights.
posted by chazlarson at 9:50 AM on February 7, 2010


This is a prime example, IMHO, of why roundabouts are superior in nearly every way to traffic lights.

They're GREAT until you put people cars in them and except them to use common sense. Heh.

In my experience, one obscured signal light is less of a big deal as well, because the rest of the flow of traffic is still being controlled by the signal, maintaining some semblance of timing and order.

When the whole intersection is out, people lose their minds without someone/thing to tell them what to do. I rarely get through such intersections without yelling TREAT IT LIKE A 4-WAY STOP FFS repeatedly.
posted by desuetude at 10:39 AM on February 7, 2010


the rest of the flow of traffic is still being controlled by the signal, maintaining some semblance of timing and order.

This is true of my in experience too. But I'd like to point out that in the specific situation that I linked to above, the intersection was way out in the boonies, and it's quite possible there were no other cars nearby except for the two involved in the accident (which happened to meet there due to unfortunate timing.)

I'm wondering this - is it true (or possible) that the more traffic there is at an intersection, the more heat build-up there is, creating some sort of micro-climate where there is enough heat in the air to melt the snow around a signal? And at signals out in the country, where there may be a much smaller number of cars passing through, there may not be enough heat around the intersection to melt that snow?

Just wondering if that could explain why this phenomenon isn't more common.
posted by SuperSquirrel at 12:43 PM on February 7, 2010


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