Many jurisdictions have begun installing LED traffic lights. LEDs use less electricity, require less maintenance, and last longer than conventional bulbs. But as the NYT reports, there’s also a catch for colder parts of the country. LEDs generate less heat, and are more prone to collecting ice and snow, which can block the signal. According to some other reports, this has led to numerous accidents and at least one death. Some transportation officials believe the problem is easily manageable by having workers go out and manually remove the snow and ice, but reduces the cost-savings from switching to LEDs.
Oren says:
Even with a small sensor and a heating element (by the way, that tech is standard on security cameras that are mounted outside in cold climes), the LEDs will probably still be far cheaper than incandescent bulbs on account of replacement costs.
January 2, 2010, 9:16 amDavid Bernstein says:
I also find these traffic lights harder to see than conventional ones in certain lighting conditions.
January 2, 2010, 9:28 amHans Clapton says:
How about “eliminates”?
January 2, 2010, 9:29 amPeteP says:
“workers go out and manually remove the snow and ice”
Hey, they promised us ‘green jobs’ – I guess this is what they have in mind !
January 2, 2010, 9:31 amOren says:
Not even close. This is a drop in the bucket compared to sending out a truck with three city workers every 9-12 months (the lifetime of a incad on that duty cycle), plus a uniform to direct traffic.
Of course, there is always the contingent that believes that the lesson from unforeseen difficulties is not to try new things. They probably can’t be helped.
January 2, 2010, 9:44 amHarry says:
The difficulty with sending workers out to clear the snow is that they will probably be busy clearing snow from the roads. The sensors & heating elements Oren mentions would have to be the way. Sending trucks out for the 10-20 storms per year would also be more expensive than the 1-2 times per year to replace the bulbs Oren suggests.
January 2, 2010, 10:05 amBruce Hayden says:
The solution then may be to concentrate on the south where snow, etc. is rare. And then move north as far as it makes economic sense.
January 2, 2010, 10:10 amPeteP says:
Oren – “Not even close. This is a drop in the bucket compared to sending out a truck with three city workers every 9–12 months (the lifetime of a incad on that duty cycle), plus a uniform to direct traffic.”
As someone mentioned, sending that same crew out 10 – 20 times a year on an emergency ( frequently overtime ) basis is a lot more expensive than doing it once a year on a scheduled planned budgeted ( regular pay ) basis.
Also, you neglect to account for the likelyhood that, given a storm of sufficient magnitude that the lights are visually degraded by snow / ice, it is likely that the streets are also thus degraded, and city workers and trucks thus busy as hell already. Therefore, it is likely that it is a few days or a week or more before they can get around to every light with that crew to clear them. You neglect to account for the costs in accidents and lives of thus having the lights either totally or partially obscured for a week, making intersections much more dangerous ( over and above the snow and ice on the road itself ).
I guess, if I may plagiarize your comment above, ‘Of course, there is always the contingent that believes that the lesson from unforeseen difficulties is not to try new things. They probably can’t be helped.’,
I might say ‘Of course, there is always the contingent that doesn’t think through the unforeseen difficulties and consequences of changing things to ‘the latest and greatest new idea’. They probably can’t be helped.’
January 2, 2010, 10:40 amSoronel Haetir says:
I’m pretty sure I saw an article while in Seattle about this. They were looking at unit heaters. I would certainly think that viable. I had a satellite dish warmer in Idaho, it did a good job keeping the antenna clear, and watching the indicator lights it didn’t run all that often despite lots of snow.
In the case of traffic lights you’re just producing heat that the system is no longer wasting. And if the units are at all like my dish warmer they should last a long time as there is little to go wrong.
January 2, 2010, 11:31 amSteve2 says:
What sort of LED signal heads are being used in Minneapolis? Several manufacturers have started making “Incandescent-look” LED heads, which place a lens over the LED matrix. This reduces the angle-dependence of the original LED heads. It also prevents that weird Light-Brite look, especially if some of the LEDs go out.
Which is another reason for the switch to LEDs – if an incandescent goes out, you’ve lost the whole phase, whereas if an LED goes out, you’ve only lost a fragment of the phase.
Incidentally, the TV news traffic reporters are invariably wrong: a flashing signal is not a 4-way stop, it’s a two way stop, same as a red/yellow flasher. Only a blank signal – no lights on at all – is to be treated as a 4-way stop.
January 2, 2010, 11:37 amChrisIowa says:
A red flashing light is stop-then-proceed. A yellow flashing light is Caution-but-no-stop-required. Most but not all intersections go to flashing red all directions on a malfunction, but some go to flashing yellow on the major route. This is especially important to keep in mind when driving in some small towns where the stoplights go to flashing after the streets are rolled up at night.
January 2, 2010, 12:02 pmAlan says:
First they wage war on my beloved incandescent light bulbs, and now this… Are there any green ideas that AREN’T counterproductive?!
January 2, 2010, 12:33 pmCloudesley Shovell says:
Just more evidence supporting the fact that the law of unintended consequences will never be repealed.
January 2, 2010, 12:33 pmarbitraryaardvark says:
Smarter traffic lights have the potential for major energy savings by motorists.
January 2, 2010, 12:42 pmIt’s 2010. We have computers in toasters. Why not traffic lights? One of the reasons hybrids save fuel is that they don’t run the engine when you are stuck at a red light. Having a light smart enough to turn green when the road is clear would get traffic moving faster which would reduce fuel use and accidents. There’s a risk of lights that are too smart, and track you wherever you go, but that can’t happen here…. A smart traffic light should be able to defrost itself.
Laura(southernxyl) says:
The sheriff knew right away that Susan Smith was lying about being carjacked by a stranger, when she said she was stopped by a red light at a certain intersection and that there were no other cars around. That red light was tripped by a sensor for cars on the cross-road so she wouldn’t have been stopped with no other cars there.
January 2, 2010, 12:51 pmJake (guest) says:
It’s nice when the tort law exam questions write themselves.
January 2, 2010, 1:01 pmAndrew J. Lazarus says:
I’ve read elsewhere in the blogosphere that the colors in LED lights are somehow easier for the colorblind to distinguish. I have little doubt that the snow-ice problem is soluble, and still with major cost savings. A different hood on top of the lights? American ingenuity, right?
January 2, 2010, 1:08 pmAbdul Abulbul Amir says:
Hoods will be insufficient amd may make matters worse. In a bad storm the snow can be moving sideways and stick when it hits.
Heaters are the only real solution coupled with a hood. Of course this means retrofitting or more likely replacing most or all of the fixtures.
At this point it comes down to a net present value calculation. Unfortunately, political bodies are usually better at calculating net present popularity.
January 2, 2010, 1:27 pmcommon_sense says:
I’ve seen this story pop up quite a few times. It amazes me the number of people who go flying through an intersection when they can’t tell what color the light it.
January 2, 2010, 1:41 pmOren says:
Yup and, as noted, the technology is already developed (including nifty sensors) for outdoor video surveillance cameras.
Cleaning the snow takes a lot less time than replacing a bulb — no more than a few minutes once the road crews have improved a telescoping-scraper-doohickey. Of course, this is a stopgap solution but it’s not so bad and should be, at absolute worst, a break-even proposition relative to the incads.
Nope. All progress depends on the unreasonable man’s belief in technological progress. You better hope we cannot be helped.
Graceful failure is always a plus.
Or scoring political points. From the Tribune:
That’s a cool $600/year per intersection, not even counting the 20-30x expected lifetime of each LED and subsequent decreased maintenance.
January 2, 2010, 1:53 pmLior says:
@Alan:
@NYT:
Replacing incandescents with LEDs has nothing to do with “environmentalism”. It’s a money-saving idea with “green” PR value. Cities continually look for cheaper solutions to existing problems. In this case splitting the light and heating elements and only heating the fixture when it snows is going to be cheaper than having a single element and heating the fixture all the time.
January 2, 2010, 2:09 pmPeteP says:
Oren – “Nope. All progress depends on the unreasonable man’s belief in technological progress. You better hope we cannot be helped. ”
If things don’t work out for you in your pursuit of the law, you have a great career ahead of you working for the CBO :-)
January 2, 2010, 2:10 pmbearing says:
I live in Minneapolis. I suspect that if you wanted to know how crews manage to remove snow and ice from traffic lights when they are already busy clearing roads, the best thing to do would be to ask the city public works department (or perhaps the columnist who answers road-related questions at the Star Tribune).
My guess would be that the same crews who are out clearing the streets — which they accomplish via a two-and-a-half-day snow emergency schedule that begins after each heavy snowfall — are also the ones who knock the snow off the lights, but I can’t say for sure. I will say that IMO the city of Minneapolis generally does an excellent job dealing with inclement weather, and I would expect them to have figured this task out by now.
January 2, 2010, 2:12 pmerp says:
The new feel-good light bulbs don’t do the job and are dangerous if not disposed of properly to boot, but that doesn’t matter. They’ll make it work and if they can’t, everybody will just ignore the problem. What’s an increase in accidents and even deaths in grander scheme of intrusive moonbat nonsense regulations.
It reminds me of the nonsensical mandatory recycling in our town. The recycled stuff is dumped at the same site as the regular garbage, requires a separate pickup, costing us taxpayers more money and causes more pollution from an unnecessary extra garbage truck route, but none of that matters. The compassionates are saving the planet and most people don’t complain because if you don’t recycle, the town won’t pick up your regular trash.
January 2, 2010, 2:14 pmChrisTS says:
Reading the NYT piece gives one a rather different picture than that provided by the OP.
Emphases added.
January 2, 2010, 2:15 pmPeteP says:
Lior – “In this case splitting the light and heating elements and only heating the fixture when it snows is going to be cheaper than having a single element and heating the fixture all the time.”
Wow ! I have a great idea to patent ! I’m gonna call it a ‘thermostat’ !!!! :-)
BTW, as someone who has worked with outdoor CCTV, I can tell you a large issue is the fact that the lights would have to each be enclosed in some sort of housing, transparent on the needed side, to retain the heat.
I’m just sayin’ …..
January 2, 2010, 2:16 pmLED traffic lights kill « Internet Scofflaw says:
[...] (Via Volokh.) [...]
January 2, 2010, 2:33 pmgeokstr says:
If we put a little windmill on top of each light, we probably could power them for free too.
January 2, 2010, 2:34 pmPeteP says:
“If we put a little windmill on top of each light, we probably could power them for free too.”
Or, better yet – if we could run little pipes to the nearest ocean, and use tidal power…. :-)
January 2, 2010, 2:41 pmpc says:
How are LEDs dangerous to dispose of? Are you confusing LEDs with CFLs?
January 2, 2010, 2:43 pmLaura(southernxyl) says:
I like the flashing signs I see that are powered by their own solar panels. No chugging generators, etc. Don’t imagine solar panels would be much good in a snowstorm.
Anyway – stop the presses – I agree with Andrew. This is the kind of thing that is fixable.
January 2, 2010, 2:50 pmTweets that mention The Volokh Conspiracy » Blog Archive » Less Electricity, More Accidents -- Topsy.com says:
[...] This post was mentioned on Twitter by Electricity Savings and Affiliates , Eugene Volokh. Eugene Volokh said: Less Electricity, More Accidents: Many jurisdictions have begun installing LED traffic lights. LEDs use less e.. http://bit.ly/4PvcZA [...]
January 2, 2010, 3:15 pmptt says:
It is my understanding that the main reason traffic lights have hoods is to block sunlight which, hitting the lenses, would reflect colored light, making it hard to determine which color is “on”. LED lights don’t have colored lenses. The light itself is generated in the appropriate color spectrum. Another function of the hoods is to darken the “off” lights, increasing the contrast with the “on” light. LEDs are already quite a bit brighter than incandescent lights, so this function is less important. If you do want hoods, arrange the lights in a horizontal row — as is done in some cities — so that snow accumulating on the hoods isn’t in front of any light.
Why not build a traffic light without hoods and with a light array with a wedge shape (sticking farther out at the top) so that snow wouldn’t have a surface to fall onto? And coat the surfaces with a material to which snow and ice cannot easily stick.
I suspect most traffic light innovations are protected by patents owned by different companies. Combining the best ideas to produce the best traffic light (with variations for different climates, of course) would require joint ventures or company acquisitions. In what appears to be a remarkably profitable industry, I doubt there’s much incentive to reduce “competition” and work together to reduce energy usage.
January 2, 2010, 3:19 pmKirk Parker says:
arbitrary,
I’ll give you the benefit of the doubt and assume you mean “light system” here: yes indeed, and in fact these things are quite common at least in Washington State. However, it’s quite a bit more than just a change to the light-controller software; you also have to bury sensors in the streets.
Even so, there can be significant problems.
First, if the pavement is concrete, it’s much harder and more expensive to retrofit these than if you’re dealing with tarmac of some kind, so many places that could benefit from sensing systems don’t have them. (I assume the city or county traffic departments are waiting until they have to do some modifications at the intersection anyway.)
Secondly, it’s possible to lose most of the benefit if the overall system is not intelligently designed. For example, most of the onramps on Highway 16 in Tacoma now feature metered access. (Whether that’s really necessary is a separate question.) The metering stoplights are always on during rush hour, but there’s no rhyme or reason I can detect as to whether they will be off or on during the rest of the day. Unfortunately, the design is completely traditional, and completely wack: there are sensors right at the stoplines, the lights default to red, and when a car drives over the sensor they turn briefly green (after a delay, if necessary, to provide for a minimum period of red.)
But typically, when the lights are on during a non-peak period, yours will be the only car coming up the onramp, and thus there’s absolutely no need to delay your entrance onto the freeway. If the system were redesigned to place the sensors at the beginning of the onramp, to detect the rate of cars entering, the lights could instead be defaulted to green and only change to cycling if the rate of cars entering the onramp was enough to require metering. (It’s quite a long onramp; this obviously might not work if the ramp were too short.)
January 2, 2010, 3:58 pmJohn Moore says:
A bit OT, but our traffic light czars in the Phoenix, AZ area have found another way of increasing accidents: they put stop-light enforcement cameras at the lights (and sometimes, shorten the yellows). The result is lots of rear-end collisions as people slam on their brakes at the first sign of a yellow.
As for snow, ice… what’s that?
They also have been installing cameras, apparently with pattern recognition software, to make the lights smarter (replacing the magnetic loop under the pavement).
Oh, and the LED lights are great.
January 2, 2010, 4:02 pmToby says:
And in the South, electricity prices are usually much less, meaning that the energy component of savings is smaller. Efforts to improve efficiency in energy use are full of folks seizing on a single aspect of service provided, optimizing for that, and discounting all others. Most lighting systems provide heat and light. That heat is a bug in some scenarios, a feature in others.
January 2, 2010, 4:18 pmToby says:
They have also given birth to a new class of porn, as the camera’s take pictures of people running lights, and some run lights because they are distracted by the passenger or themselves have their attention focused on the passenger. When you combine this with date nights and alcohol, there are more than a few shots that are passed around, and at least one that is part of a divorce proceeding.
January 2, 2010, 4:23 pmAnthony says:
It’s not counterproductive, it’s just not for everyone and everywhere. There are plenty of places where this is a total nonissue, and even where this is an issue, it’s only a factor when there’s enough snow to gum up traffic lights and not enough to close the roads completely.
As for solar powered stoplights: I haven’t seen any of those, but I’ve seen plenty of solar powered construction warning lights. It’s a convenient way to power a portable road sign (grid power is unavailable, and fueling and maintaining a portable generator is more expensive than a solar panel).
January 2, 2010, 4:27 pmerp says:
pc said, “Are you confusing LEDs with CFLs?”
Yes and I’m sorry that I haven’t kept abreast of the breakthroughs in light bulbs.
Thanks for the correction.
January 2, 2010, 4:43 pmAllan Leedy says:
Can’t this problem be solved with a little driver training? Don’t most traffic laws provide that if the light fails at a signal intersection, all drivers must stop before proceeding? I guess it could be a problem if the light is visible in one direction and not another, but that could be solved just by switching it off.
January 2, 2010, 6:13 pmLeo Marvin says:
Shame on you, piling on Donald Rumsfeld.
Or better better yet, we could run little pipes to geokstr, and use geo-thermal power :-)
January 2, 2010, 6:33 pmSteve2 says:
Huh, this may be a locally varying thing, then. Every signal system I’ve ever worked in (all in Virginia), we set the major road to flash yellow and everything else to flash red if there’s a malfunction. I’ve never done work somewhere that set signals to flash all red, but like I said, I’ve only done work in various Virginia locations.
Hoods are also among the methods that can be used to prevent a signal from being visible to the wrong people (for instance, at an intersection where two roads are at an acute angle, to make sure drivers on one can’t see the signal heads for the other). They don’t restrict the angle as much as louvers do, but by the same token they don’t reduce the light output the way louvers do. And some LED lights do have colored lenses – the ITE VTCSH-LED specification for LED signal heads calls for a lens to achieve an “incandescent look”, and several manufacturers offer the lenses in colored and uncolored versions. Smart cities buy uncolored lenses, of course, since colored lenses are redundant over colored LEDs and have that sunlight-makes-them-look-on risk. The hood’s good practice, regardless.
Not a lot of places (none that I know of) are actually putting pavement loops in anymore, even to replace existing in-pavement detectors when they go bad, because of the maintenance difficulty. Mostly what’s used now is video detection: a closed-circuit camera is pointed at the spot of road where an in-pavement detector would have gone, and that camera’s hooked up to the computer that controls the signal. That’s what cameras like this one are for.
January 2, 2010, 6:38 pmAnym_Avey says:
However, it’s quite a bit more than just a change to the light-controller software; you also have to bury sensors in the streets.
No, not necessarily. As someone already noted, overhead detection systems have been available for some time now. However, it will require retrofitting the light controller and taking the intersection offline for extended periods…which is probably why most upgrades are done by rebuilding the entire light system at the intersection and leaving the old system in service until the new system is operable.
Unfortunately, this process is expensive.
The sheriff knew right away that Susan Smith was lying about being carjacked by a stranger, when she said she was stopped by a red light at a certain intersection and that there were no other cars around. That red light was tripped by a sensor for cars on the cross-road so she wouldn’t have been stopped with no other cars there.
“Suspected”, not “knew”. Lights of that nature are sometimes programmed to force a cycle periodically, just in case a vehicle has somehow approached the intersection without tripping the detector.
January 2, 2010, 7:01 pmLaura(southernxyl) says:
The problem there is that people are prompted to stop when they see a red light. In conditions where there’s snow and ice, when the landscape looks different than it normally does and people are focused on controlling their cars and not having them slide all over the road, an unlighted traffic signal is too easy to ignore. I know, I’ve done it, even on roads I was familiar with and I knew the thing was there. (No wreck, thank God.)
January 2, 2010, 7:02 pmA. Criminal says:
How are LEDs dangerous to dispose of?
You can get led poisoning. Trust me.
January 2, 2010, 7:31 pmLouis Villaescusa says:
The answer is “half-hats.”
The cylindrical light shields that are in front of most traffic lights resemble the “top hats” that we place over some lighting fixtures in the theater.
When we don’t want 360 degree shielding we deploy “half-hats.”
Just cut the bottoms off of the cylinders so that the snow will fall away.
January 2, 2010, 10:09 pmreadery says:
Actions can often have unintended consequences that simply can’t be foreseen at the time the action was taken. The city councils did their best with the information available to them at the time.
These complexities and unintended consequences are a key reason to leave decision-making to legislative bodies, which make decisions based on attempting to discern real-world consequences (inductive reasoning) rather than deducing applications from abstract principles (deductive reasoning).
Imagine what would have happened if a court had inferred from a constitutional provision a requirement that cities switch to the LED lights. Respect for the judiciary, and the constitution, would be diminished.
Similarly, the judiciary should be reluctant to impose liability based on information that became known in fact only after the decision. Doubtless the medical profession should have known that disease was caused by germs for centuries before anyone actually discovered it. Doubtless we all, in hindsight, ought to have been better at foreseeing what was to come than we actually were beforehand. Everything is obvious in hindsight.
January 2, 2010, 10:10 pmeny says:
GPS should be installed with sound alert
January 2, 2010, 11:48 pmMike McDougal says:
How do you know that? In all my driving years, I’ve never seen an incandescent traffic light being changed.
January 2, 2010, 11:57 pmAnatid says:
Oren, out of curiosity, are you a younger sibling?
January 3, 2010, 12:17 amKirk Parker says:
Anym_Avey,
Good point. The systems here, even the recently-installed ones, appear to all use buried sensors; you can see the tar strips where they’re installed.
January 3, 2010, 1:27 amKirk Parker says:
A. Criminal,
Wow. In a just world, you’d receive an intensely cruel and unusual punishment for that!
January 3, 2010, 1:29 amDan D says:
Clearly, the environmentally correct solution is widespread global warming. Why should our noble energy saving measures be subject to the tyranny of snowfall?
January 3, 2010, 10:15 amerp says:
Mike, I’m with you. I’ve been driving for over 50 years, lived in many different states, driven all over the U.S., Canada and Mexico and I’ve never seen a traffic light bulb being changed either.
I wonder which of the compassionates has an monetary interest in this new technology. Reid comes to mind. His city uses an awful lot of light bulbs.
January 3, 2010, 10:36 amlonetown says:
What a perfect opportunity to create some good paying jobs driving around clearing snow off the traffic lights!
January 3, 2010, 11:40 amAndrew Gradman says:
Lives can sometimes be exchanged for money. This is a troubling but inevitable state of affairs. The solution provided by economics is controversial, but it not prima facie wrong.
What troubles me is that the decision to apply this solution has been made, not democratically, but by “officials”:
Applying economic calculus to lives is the gravest decision a democracy can make. Decisions of that gravity are the domain of legislatures — in fact, they are the reason we have legislatures. For me, the story’s takeaway is this: democratic theory has no clothes.
January 3, 2010, 4:14 pmLeo Marvin says:
I’m guessing you’ve never worked a night shift. Because I have, and I’ve seen it many times.
January 3, 2010, 4:21 pmlgm says:
You guys seem to like cost benefit analysis. As you should be aware, that starts with numbers. In this instance, the numbers seem to be going against you. Yes, there are costs with LESs, but the energy savings seem to outweigh the costs, even in snow bound places.
January 3, 2010, 4:23 pmBrooks Lyman says:
The problem with some of the suggested solutions such as hoods, sloping lenses, etc. is that the snow/ice buildup comes when the snow or freezing rain is driven horizontally by the wind; wet, sticky snow or freezing rain will adhere to any upwind surface such as signposts, tree trunks and traffic lights. I doubt that some sort of coating on the lenses will help much in that situation (and will eventually wear off, anyway). The solution is a heater with a thermostat or possibly some more sophisticated snow/ice sensor so that one doesn’t heat the lights from November through April when you actually need to heat them a few days a year. It might also be possible to have the heaters remote controlled by wireless from the highway department headquarters.
As for LED lights themselves, someone noted that they are brighter than incandescents. I will vouch for that; some of the green traffic signals in my neck of the woods (Central MA) are so bright that at night, they make it difficult to see what is beyond them. I suspect that the designers made all the lights the same brightness without taking into account the eye’s increased sensitivity to green. That’s OK, just so long as these clowns aren’t designing bridges or airliners….
January 3, 2010, 7:33 pmjay says:
What this means, is simply that when you try something new, you need to adopt it gradually, as you ascertain the implications. As people had pointed out, none of these are unsolvable problems, and over the years will be handled along with savings.
The problem is when top-down management attempts to demand particular solutions be adopted en masse.
January 4, 2010, 12:21 pmJohn Moore says:
But I’ll bet you’ve seen them burnt out, which is a much better test.
January 4, 2010, 9:17 pmerp says:
Not really John, I can’t remember seeing even one burned out bulb.
January 4, 2010, 10:17 pmPolitics and Probabilities « The New Print says:
[...] shall we? I’ll do my part by continuing to point out irrational calculations like how LED traffic lights may be causing more accidents and costing more money. You just keep reading and [...]
January 4, 2010, 10:46 pm