LED traffic lights don't melt snow, do cause accidents
By Vlad Savov 
posted December 17th 2009 9:16AM
posted December 17th 2009 9:16AM
A number of cold weather American states are reporting their dismay at finding out that LED traffic lights are so energy efficient that they do not produce enough excess heat to dissipate any snow that covers them. It turns out, perhaps in an homage to bad engineering everywhere, that the inefficiency of incandescent light bulbs was previously relied upon to keep traffic signals unimpeded. The new LEDs do not achieve the same effect, which has resulted in a few accidents and even a death being blamed on obstructed traffic lights. Feel free to apply palm to face now. It's not all gloomy, though, as the majority of people are said to treat a dysfunctional traffic light as a stop sign (how clever of them), and a tech fix is being worked on as we speak.
That's pretty awesome. Not the accidents of course, but how we tend to not think of or realize certain things sometimes. The question now is, would it be more efficient to add heating elements to the fixtures of switch back to bulbs.?
@(Unverified)
Not if they can manage to do it smart, only have the heater on when needed, not constantly.
@(Unverified)
It still seems like a stupid mistake. You'd think that in a project like this there would be many people involved, amongst them some who work with traffic lights in colder regions...
@(Unverified) Not trying to be a doodoo here, but USA has that kind of a reputation around the globe. "Do first, think next. And if you can make it bigger do it!"
@(Unverified)
Just retrofit a non-reflective, transparent flush cover. Bad design, bad testing, just too bad.
@(Unverified) But you are. At least we do shit. It's more than other POS countries can say.
@Canucker
You're assuming that gravity would take care of the snow build-up, but that's simply not true. Wet snow can stick to just about anything. I assume you don't live in a cold region or you would know this.
@(Unverified)
Or just coat and/or design the housing so that snow doesn't build up. No need to actively MELT the snow. Water has high heat capacity. Melting it to remove it is inefficient.
@(Unverified)
Last I checked, the US is not the only place LED traffic lights are used...
@(Unverified)
What spend millions of dollars to research some new expensive heating element to add in the lights?
I figure it's cheaper to go back to the old lights where the light IS the heater.
I saw a story similar to that a few months ago (not sure if it was Engadget or elsewhere)
About how the energy savings of switching to LED bulbs was wiped out by higher heating costs due to the loss of the extra heat from the old bulbs.
@Ken J I would agree that material to which snow would not stick to, would be the ideal solution, as well as improving the housing design.
@(Unverified) - Heating elements will add more to the cost of running the lights than just switching back to incandescent bulbs. LEDs are awesome but come on, who didn't test their products in the colder climates in the US before deploying them?
Honda tests its new cars in cold climates before rolling out to the nation and so do most companies deploying products in cold and warm climates.
Are we are so busy insanely following the current AGM hysteria and putting toxic CFL lightbulbs in our homes that will ultimately end up in landfills leaching into local groundwater - that hopefully - LEDs won't take a perception hit because of this. I want LED bulbs in my house but not so I can "Save the Earth.", so I can save money.
Better yet, how about those new CRT based light bulbs? I wonder how much heat they generate. I know the light from them is much more natural than CFL or LED.
@(Unverified) Clearly the best solution would be to fire laser beams at the lights to melt the snow. All cars should have hood-mounted lasers, obviously. Much safer than hood-mounted flame throwers, although having both would be awesome.
@(Unverified)
I guess they thought that the salt was going to jump up from the ground and spray tself on the lights!!!!
HAHAHA!
EPIC FAIL on engineers who designed this!!!!
@Ken J
"Or just coat and/or design the housing so that snow doesn't build up. No need to actively MELT the snow. Water has high heat capacity. Melting it to remove it is inefficient."
You don't need to melt all the snow, just a very thin layer to reduce the friction between the snow/ice and glass. Then, gravity takes over.
@scjessey Or we could build a giant tank under the lights, and put sharks with frikin lasers attached to their heads...
@(Unverified)
We engineer for what we need, which, in this case, is efficient lighting. No matter how useful heat would be in such a situation, it is a waste product of energy conversion. If the heat is indeed necessary, add it externally, so it can be switched off when not required.
@(Unverified) a line from Home Improvement comes to mind "measure twice, cut once" - seems the PM on this project needs to be fired.
POWER IT WITH STEORN. LOL
@(Unverified)
Actually, no it wouldn't be cheaper to switch back, the old style bulbs use significantly more electricity than the LED bulbs not to mention the labor costs of getting someone out there with a bucket truck to replace the bulbs when they burn out, old bulb use a ton of electricity 100% of the time, but you only need the heat to melt the snow maybe a couple hundred hours worth of time a year and even still a heating element would likely use less power than the old bulbs as halogen/incandecent bulbs get extrememly hot, much hotter than is needed to melt snow.
And on top of it all i'd wager there are far more accidents caused by burnt out bulbs than a snow obstructed bulbs.
@(Unverified) Though in the summer, incandescent bulbs could cause us to spend more money on air conditioning due to the excess heat.
@(Unverified) solution, install Oregon scientific thermometer at intersection, when temp reaches 32F turn on heated coils around each LED...
@(Unverified)
No No No everyone has it all wrong. The bigger problem is the cold weather. My solution is to pump gasses in to the atmosphere changing the climate of the earth. That way you can have all the energy efficient bulbs your little green hearts desire.
@Canucker : "Just retrofit a non-reflective, transparent flush cover."
Look at the completely flat sign next to the light. It's covered with snow. Being flush won't prevent show buildup.
@Erb People like you should work for DOT :) What is a low cost/tech option could also be to simply change the shape of the glass to a more conical shape, that way hopefully a portion of the light will remain unobstructed in heating failure.
@Ken J: Er, We could coat all of these surfaces with teflon, and wait for it to leach through rain water into our drinking supply. Jolly good design.
@(Unverified) Two words: Flame Thrower. All we need then is an all-wheel drive mini-van for some drive-by snow-melting action.
@Canucker
I dont think that would work, unless they really got the surface right, snow will still build up. maybe if it were angled down some. or maybe they can have some one come by once every couple weeks and spray it with Pam or somthing
All you have to do is change the flashing around the lights...
The vented sides allow the wind to blow directly into the lights and collect now there. Non-vented sides have a tendency to force air to go around the lights, so less snow sticks.
Also, change the foods so that there's less space for snow to stick. Gravity will do the rest.
It works great in Canada! There's four feet deep snow drift outside my house, but I can still see the traffic lights! (that is if I can get my car out of the drive first)
@Erb
ditto, heater activated via thermometer or auto defroster...
Spray some silicone spray on it, done, seems simple and obvious too.
@fiver In this case, heat is not a "waste product."
@sandra
Adding a 500+ watt heater to an LED array is much more inefficient that using 100-150 watt incandescent bulbs.
People seem to be assuming the drive for LED traffic lights is energy savings. That's actually only a side benefit. The real savings is that they don't have to be replaced very often. This was assuming that some expensive retrofitting wasn't going to be necessary, of course.
@Patriot
CFLs are hardly "toxic" The amount of mercury left over from the life of a CFL is less than the amount of mercury made as a byproduct of the additional electricity a normal bulb would use. In addition you can recycle the unused mercury in CFLs (all Home Depots accept them, as well as many other places). The trace amount of mercury is so minor that you don't even need any special clean up procedures if one breaks in your house. More facts and less hype, please.
I beg to differ that a "majority" of people use a dysfunctional traffic light as a stop sign. Just the other day there was a power outage in my area and people were zooming through the traffic lights as if they were never there. Even saw a cop do it too. It just surprises me how many people get their drivers license without even knowing the more basic of driving rules.
It's tricky because the lights are probably only blocked in one direction. The other three sides of the intersection work as normal, but since the wind blew the snow from one direction, it appears to be a dysfunctional light from that side only.
@verruckt8
They knew the rules when they got their license. But they forgot about them the next day.
@verruckt8
I live in Columbus, Ohio, the home of bad drivers in bad weather. When Hurricane Ike came through and knocked out power for a week, the police promised to direct traffic at all major intersections. I wish they had kept that promise. I saw two cops all week and both were speeding through an intersection. All week, I saw one intersection where people were treating it like a four way stop. Surprisingly, I saw no accidents that were caused by this. We could have used those officers directing traffic.
@verruckt8 I really agree with this... I have seen it more then a few times myself. Then again most lights here have flip down Stop signs and I have almost never seen them in use when the lights are disabled.
The over all issue of the LED traffic lights not working to melt the snow is a big issue here in WI. There is talk about stopping the use of LEDs for that very reason.
@verruckt8 It is not because drivers doesn't know how to drive. It is all about moral principles and peer pressure. You know you do something bad that wouldn't cause a consequence, you'd do it.
Honestly, ask yourself, would you loot during a riot or black out when everyone is doing it? The dude or gal next to me is doing it, IT SHOULD BE FINE.
drivers don't*
@tommy2468 Alright, I have to say it. I'm guessing then if everyone was jumping off a bridge you'd do it too? It would be alright? (Most) people would not loot during a riot if they believe that stealing is wrong to begin with. You see more people loot during a riot because of the opportunity not because they lose their moral standards because everyone is doing it.
I challenge you to randomly ask people what they should do if a traffic light is not working. I bet you'd get a lot of people either not knowing or giving you the wrong answer.
@verruckt8
Hmm... In my area people seem pretty good about handling outages. On slower traffic lights they'll treat them like 4-way stops and in heavier traffic areas they'll act almost like the light is still there... one side will drive for a minute and then they'll come to a stop and let the other side go for a minute. Obviously there are still assholes that will drive on through even though everyone else is stopping so you have to be careful as the transition is happening, but overall I've had generally good experiences.
@spurgen8r
Doesn't matter. If the peope that are going the direction of the blocked light use it as a stop sign, they won't get hit by cars coming the other way.
@verruckt8
Maybe they COULDN'T SEE THE TRAFFIC LIGHT when the power was out. Everywhere I've lived, drivers are pretty good about treating dead or flashing red signals as all-way stops. But if the power goes out at night, there will be a fair number of people who don't see the intersection.
@verruckt8 Here's something for you--if somebody followed a crowd in jumping off a bridge, it would go against basic human nature to be beneficial to themselves (such as easy loot), and avoiding of any detriment (such as drowning in a river under the bridge). Point is, if you can get away with something that does you good, then you'd be inclined to do it, but not if it fucks you up. :P Same applies to barging through a junction--it makes your journey quicker.
Anyway, I'm sure that we can all agree that some people are just plain stupid on the roads unless they have really obvious cues such as visible traffic lights.
@Deed if everyone is jumping of a bridge u better jump too there has to be something terribly wrong for everyone to kill themselves like that.
@verruckt8
You sir, are awful at this. What you have explained there is something an ethical person would do, not moral. Dee dee duh
Wait a second, I know for a fact that Audi already dealt with this and the other thermal management aspects of LEDs that make them a bit of a challenge to use where incandescents or halogens were used before.
How else do you think virtually all their cars employ copious LEDs for daytime running lamps and even normal headlights?
The solution is obvious, some very low current heaters for wintertime.