LED Lights Don’t Melt Snow on Traffic Lights, Hiding Signals From Drivers
Jan. 8, 2010
A huge swath of the country is getting snow and it’s raised an unusual and potentially dangerous problem for motorists.
Click picture to see report
Communities across the country are converting to LED traffic lights, but these lights don’t emit heat, so snow doesn’t melt like it would with a regular incandescent bulb. In some cases, Drivers then can’t see the signals.
During a snow storm last year, Lisa Richter of Oswego, Ill., had a green light and was turning left. But police say a driver in the oncoming lane blew through his red light and plowed into her, killing her instantly.
This wasn’t a regular accident. Police said this traffic light, blocked by snow, contributed to the crash. The light was an LED signal, which doesn’t emit heat, so snow doesn’t melt like it would with a regular incandescent bulb.
Cities and states across the country that have converted to LEDs report an energy cost savings of up to 80 to 90 percent.
In Green Bay, Wisc., where all traffic lights are now LEDs, December’s incredible snowfall caused many to be packed with flakes.
After their intense storm last month, some drivers in Madison, Wisc., noticed their neighborhood LED signals were hiding.
“I know that the stoplights are there, but if I didn’t, it would have been very easy to fly right through them,” one driver said. “And especially with the off ramp right on the interstate, it could be a very dangerous situation.”
The state of Wisconsin switched to LEDs in 2002 to achieve the massive energy cost savings. Maintenance costs are also much lower because LEDs last a long time. Incandescent bulbs usually have to be replaced every 2 years.
“With LEDs, we have some of our heads that were installed in 2002 still operational today,” said Wisconsin state traffic signal systems engineer Joanna Bush.
Another advantage of LEDs: Bush said the old incandescent bulbs could pose safety problems of their own.
“When they fail, they go dark, like a light bulb at your house. There’s no warning and it’s dark. With the LEDs, it’s a string or two that starts to go out and the driving public might not even notice a change in the LEDs and we can get our crews out to change it.”
Yes, but you’ll need crews to go out and scrape ice of the lights, creating some of Obama’s new green jobs.
For what it’s worth, the push to LED traffic lights appears to be motivated largely by significant savings in electricity and maintenance costs, rather than by green pipe dreams. For once these are the unintended consequences of government doing something smart, than of government doing something stupid.
“Not a problem in warm states, but a problem where it snows.”
Great! It’s only safe to install them in Hawaii!
And Puerto Rico!
Why is this a surprise? People who have used LED lights have known this for years. The traffic engineers in cities using them in traffic signals should also have known, and been doing something about it. A small heating element in the light fixture, perhaps? Sounds like a lot of lawsuits waiting to happen to me!
The easy fix is to not have the shield that collects the snow, especially since LED’s shine brighter and don’t need to have the light directed.
The more expensive fix would be to convert alot of those intersections to roundabouts. By doing so, it makes people more aware of the traffic that is moving around it. I saw an interesting story on one of the cable news stations about a month ago. Some town in Norway took down all of it’s traffic lights and replaced it with roundabouts and has improved traffic flow almost 80% and has cut down on traffic accidents.
Media gets it wrong again!
LEDs do emit heat, just not a whole lot.
They are more efficient and thus produce the same light with less wattage dissipated in heat. They are substantially more visible in situations where glare is a problem. Which poison do you want?
Dunno, how biug a problem is this really? I mean how much snow do you have to pack a LED light before you can’t see it at all, and then how many drivers really won’t stop and look around at a defective light?
As to the heating thing, it would have to be pretty smart with some secondary sensor, otherwise you are throwing away the energy savings.
I’d be worried that all that : heating element + snow pack sensor + whatever would be deeply unreliable in actual service conditions. After all lights are defintely onthe severe duty service list: water, sun, heat, cold, wind, vibration, general pollution…
Well, personally I prefer them! They’re more reliable than conventional bulbs, give a more crisp light, and use a lot less battery. It’s not too difficult to think that you need to clear snow off them before you drive off, and periodically (if you then drive through a snowstorm). I’ve seen idiots (Gores to you US) all this week in the UK who can’t clear snow off their windscreen (windshield to you US), off the bonnet (hood to you US), or off the roof (roof to you US). They are then shocked when a lump of it falls off as they’re driving along. They ought to use their loaf (head to you US).
starzmom
If this was known and is known, and cities install them anyway, then they are liable for any death, injury or property damage that results. Companies could never get away with this.
If governments are allowed to, then it is yet another sign af out-of-control government power.
For Americans, a roundabout is a so-called traffic circle.
What should this illustrate? The danger of saving energy by switching to LED instead of incandescent light? How about all other traffic signs that snow over?
It doesn’t have with climate to do at all. It’s typical of the fear for all that’s not as it used to be. Father never used an LED.
LED lights are superior. We notice them going out more now because of two things:
a) failing LEDs is a rare event and,
b) a lot of LED stoplights were installed at the same time in the early oughties, when the technology first came out, and are starting to hit an uptick in failures as they near end of life, esp in harsh environmental conditions.
It is truly worth it to use LED lighting, it reduces power consumption by 90% over incandescent, and given the percent of our national electric supply that is consumed by lighting, converting all of our lights to LEDs would mean a rather large conservation.
According to this:
http://www.cee1.org/eval/db_pdf_es/275es.pdf
22% of US electric consumption is in lighting. Converting to LED lighting nationwide for everything would therefore reduce consumption overall by 20%. Given electric production is some 70%+ based on carbon emitting fuels, a reduction in emissions by 17% would put us below our 1990 emission levels for a good few years without a significant economic burden (in fact, LED’s have a ROI of under two years, so the economic benefits are actually positive).
The solution seems simple to me. Have a small heater in the traffic light that is controlled by the temperature. Below zero and it switches on, above and it switches off. The electricity saved over using halogen bulbs (which is what I think traffic lights use) will still be substantial.
This doesn’t sound like a real problem, if there is no light showing then slow down. There would have to be a lot of snow before you could not see that there were lights at the junction.
Didn’t the US pass a law prohibiting the sale of incandescent lights by 2010? So maybe the local governments changed them to comply with Federal regulations…
Time for the engineering types to come up with a new design for traffic lights. I am sure there are a variety of designs that could fix this problem from a sensor that switches on a heating element to an angled lens with a silicone slick coating that snow will not stick to.
starzmom (06:26:37) :
The traffic engineers in cities using them in traffic signals should also have known, and been doing something about it.
____________________________________________________________________
In principle I agree.
But, it’s not so easy to go against the flow. Especially when the flow is supposedly saving the world.
There’s a whole lot of things going on that someone somewhere along the line should known better and said something. Some probably are saying something. But their objection alone isn’t enough to stop ‘going green’.
Going green is pretty much everywhere you look. I saw a FedEx commercial where they said they didn’t have wood tables because the went green. I saw metal in the new table legs…..(scratches head)….. I can’t see how metal is ‘green’-er than wood—but that’s another topic.
All the record cold and snow though is slowly but surely changing the momentum AGW and ‘going green’ has. But I think even if the world goes in to a modern day little ice age there will still be a small percentage of people talking about global warming and ‘going green’ to save the earth.
So, don’t be too hard on city engineers. They might be good folk.
Record cold and snow in the past two days, Thursday and Friday, in the US. Florida is getting it the worst. But Watts Up With that red dot in Florida??
http://mapcenter.hamweather.com/records/2day/us.html?c=maxtemp,mintemp,lowmax,highmin,snow
anything but new roundabouts! They used to be very popular in the 20’s and 30’s; just about every Texas town had one at the main intersection. They have just about all been eliminated now, thank merciful heaven! (I still know of a couple on the outskirts of Waco and Ft. Worth) They have always been deathtraps, I think when the Dallas roundabout was finally demolished a few years ago the death toll over it’s existence stood at about 300 or so. Sure there are yield signs and speed limit signs – I’ve been on them, still everyone enters at 70mph and just hopes a spot opens up when they get there.
In horse and buggy days, they were great -but today, they’re just a nonstop demolition derby.
In the past 2 days alone in the US 277 cold records and 417 snowfall records.
Many roads from San Antonio to across the deep south have ice. Atlanta is especially icy.
In Florida they say they’ve had ice and frost like this before but never for this many days in a row. The farmers are going to be hurt financially by it.
How about increasing the CO2 content of the atmosphere until all snow melts? Oh wait…
All they need to do is put a sensor which detects when temps drop below 32 and activate a resistive non-light emitting heat source. Problem solved.
I generally like the LED traffic lights. However, in my area I have noted a failure phenonmenon: The greens seem to have a large number of failed, or failing individual LED’s. The reds and yellows seem to be holding up much better. I haven’t taken a statistical sample, but maybe I will in the next few weeks. I deal with atomic and molecular physics rather than solid state, but I would guess that the dopant for the greens may change the substrate such that temperature extremes are not tolerated well. Could also be the stress of constant on/off cyles.
In the Christmas Eve snowstorm we had in North Texas, it didn’t take long for the LED lights to develop visibility problems. The snow and sleet were blowing sideways in strong winds. If you were driving on unfamiliar roads, as we were, the “hidden” traffic lights were a problem because visibility was poor anyway. Not a reason to give up on LEDs, but there will ultimately need to be another techno-fix to address this particular issue.