Archive for: traffic light

LED shortcoming: Traffic lights in Chicago not hot enough to melt snow build up. Accidents on the rise.

  • December 16, 2009 8:52 am

snow-lightEnergy efficient traffic lights seem like one of the best ways to save local governments significant amounts of money of the course of 5, 10, or more years. The lights which often use LED technology are much less demanding on the power grid which in turn means more money for other things. But there’s one side effect many have overlooked. Heat output.

Remember, the higher the heat output of a light, the more energy is being wasted. That’s all fie and dandy for indoor lighting or lighting or “non-critical outdoor lighting”. You see, the city of Chicago is discovering that the lack of heat output because of the new LED traffic lights’ increased efficiency is actually creating another problem — increased snow build up leading to a higher number of accidents.

It’s an easy concept to understand. Traditional traffic lights generate heat which in turn melts the snow off of the actual lights keeping them free and easily seen. LED’s with their much lower energy consumption and heat output allow snow to build up as temperatures aren’t getting high enough to melt the snow. It’s a sad side effect really as now numerous people are being injured and potential lives lost. Even still, it would be foolish and hasty for the city of Chicago to backtrack on their “green rollout” by replacing the more energy efficient traffic lights with the older style simply to melt snow for a few months out of the year. Though for an easy and quick fix, swapping the lights may be the only answer.

I’m not a civil engineer in Chicago so I don’t know how they went about the big switch to LED bulbs. Can they simply replace the bulbs with traditional lights or do they need to change the entire fixture? On the surface, such a switch seems like the best way to go as I don’t see any quick, easy, and cost effective way to “warm up” LED traffic lights. Future models of LED traffic signals could have an electric heating element of some sort built into the light housing as to melt the snow. But again, that doesn’t help the thousands of currently deployed lights on the streets. Not to mention, adding such a feature will no doubt add to the cost of energy efficient traffic lights — lights which are already a fair amount more than traditional lights.

Of course, cities employing LED traffic lights have another option — have city workers clean of the bulbs by hand. It’s not quick and it isn’t exactly a very good “fix”. For the time being however it is the only viable option to keep the LED’s and reduce traffic accidents.

To highlight the point further, many cities in Wisconsin have been migrating to LED lights for some time now. In fact, there are so many “modernized” traffic lights — numbering in the hundreds — that the state is saving over $750,000 per year in energy costs. It may not seem like it would make a huge dent in the state’s budget, but every little bit helps. Not to mention, I’m sure their are more than a few hundred traffic signals in Wisconsin. Just imagine the energy savings if all of them were converted to LED. Simple solution: Take a tad of that savings and hire an extra body or two during the winter months to aide in cleaning LED traffic lights off. Sound easy enough?

Some will never be pleased however as several are calling for the city to abandon the move to LED traffic lights until a new design emerges that can actually be self sufficient in cold, snowy weather. Such things are again short sighted. While a price tag can never be placed on a human life, removing technology — a very needed and important one at that — simply because of a minor problem is a bad decision.

Any Chi-town residents care to chime in? Have you personally witnessed any accidents due to LED lights being covered by ice and snow?

Chicago Tribune

Solar Traffic light looks slick. Trees, furry animals, and mother planet drop a smile.

  • October 21, 2009 6:57 am

Traffic lights are ancient tech. All it is — a light on a traffic controlled sensor. Heck, cheaper counties and local governments such as my own aren’t even that technologically savvy opting for the ‘ol timer controlled method. And we all know how much those suck. We’ve all been there, sitting at a red light with no one in sight. All is not lost as one saving grace from Cheng-Tsung Feng, Yao-Chieh Lin and Bo-Jin Wang is truly impressive if not a rehashed subject. Solar powered stop lights make all the sense in the world. Free energy! During the day, the sun powers the lights while a battery backup system keeps them going throughout the night. Traffic lights are a very function over form type of device and that’s ok because how often do you really comment on the styling of your local traffic lights? That’s what I thought. Never.

Another issue with current traffic lights is their stacked approach. Why use excess materials and energy with the common three bulb layout when you can use one? Again, the designers mentioned above had hit another homerun as this solar stop light users a discolor LED allowing red, yellow, and green (or whichever colors your locale uses) to all be displayed within one unit. Sadly, this concept is just that, a concept. Still, I’m reserving some hope that some city, somewhere, will take it upon themselves to make these swanky lights a reality. 2040 here we come.

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