It's probably a good idea to design a fixture so that it can be refurbished. This is especially true given the pace of LED development. When more efficient LEDs are available, you send the fixture out to be retrofitted with new LEDs for less than the cost of a new fixture. Even when an LED fixture is disposed of, a lot of it can be recycled. The aluminum heat sinks are quite amenable to recycling, for example. Let's not forget that disposal of large numbers of lighting fixtures is nothing new. What happened to all those old T12 fixtures in offices and stores, and the pcb-laden ballasts which powered them? That probably represented more toxic waste than any future LED fixtures might.
They ought to standardize a few package shapes/styles so that in the future you can easily upgrade/service your LED fixture. I fear though that with the short attention span the industry has, there will be a mess of "standards" the first few years. Kind of like how old mobile phones all had charger/data connectors that LOOKED similar, but would never be interchangeable until recently now most phones use a mini USB for power/data.
In the end we can probably design an LED ballast to last for many decades by paying attention to the heat. Retrofitting the LEDs when they dim appreciable every decade or two can be designed into the fixture. Fact is electronics of all types are getting ever more reliable if made properly. It's probably not unreasonable to expect a well-designed LED fixture in an indoor environment to last as long as the building it's in. I think once we get past the screw-in disposable bulb mentality there will be a lot of incentive to design better residential fixtures. Commercial fluorescent and discharge lamp fixtures already easily last 20 or 30 years.
The other mentality we need to get past is the gotta-have-it-as-cheap-as possible-so-build-it-in-China" mentality. The real reason why "Made In China" (and other dubious manufacturing locales) is getting such a bad rep is because American corporation are too short sighted to care about the longevity of a product when the initial profit is the overwhelming concern to themselves. And in turn, the Chinese manufacturers themselves know that they won't necessarily be held accountable for defective equipment when they intentionally cut corners. Even if they are held accountable, there are many other businessmen knocking at their doors to build the next hot item at Wal Mart. Yes stuff made in other countries can be good, but there is little accountability on the manufacturers end for them to care. Remember, they need to fill several shipping containers to make it economically viable before anyone catches on to the low quality product it's already too late.
We're still on a steep learning curve with LEDs. Some of the premature failures can be attributed to that, most are just due to poor design to save what amounts to pennies. For example, many Christmas lights are half-wave rectified without filter capacitors. I'll gladly pay the extra twenty cents per string that these parts will cost to avoid flickering. I think most consumers would.
Unfortunately, I bought Philips brand LED xmas lights last year. VERY high quality sets as far as build goes. However, I was so turned off by the 60hz flicker I have not even used them yet. I love the pure color and sparkly brightness of them, but as soon as I move my head the flicker annoys me. What a terrible oversight by a respected name.
Again, when cost is the primary concern in a disposable society....
Too bad though since technically LEDs should last a long time, they still find ways to end up in a dump anyway despite all the hype. If not for 60hz flicker, it'll be sub par plastics, defective wiring, poor QC, poor engineering, etc etc that will surely doom most LED sets to a short life.
Seriously, I would refuse delivery of a product like that. For any application of 5mm LEDs where reasonable life is expected I would drive at 10 mA tops, better yet 5 mA. I'll bet they're probably using the cheapest (i.e. least bright) LEDs they can get which is why they're baking them to death. I'd bet decent LEDs driven at 5 mA might well be as bright. Fact is despite the common 20 mA rating for 5mm LEDs, 5 to 10 mA is really about the most you should drive them at unless you're happy with life of only a few thousand hours. If you drive at 5 mA, use decent LEDs (Cree or Nichia chips), and have wide copper traces for heatsinking, you might well get in excess of 100,000 hours (about 25 years on a typical duty cycle) out of your green LEDs. One thing LED traffic lights have going in their favor is they're not a continuous duty cycle. The LEDs can cool during the 30 seconds or so that another color is on.
The traffic signal modules have standards they need to meet for color, luminous intensity, beam pattern etc. These 3M modules are about 4-1/2" in diameter and expected to replace a narrow spot 150W Halogen PAR lamp. It's a tough life. We actually have been sending back to the manufacturer for warranty.
Some LED traffic signals are almost always continuously "ON". During certain periods, an intersection may rest in green on the main street. Anyways, the above problem only applies to the small 4-1/2" green modules. The other modules are these big honkers that weigh about 2 pounds and are either 8" or 12" in diameter. The green ones (signal green LEDs are not long lived for some reason, aren't they GAiAs? I think the signal green LEDs are a newer chemistry) don't last very long. Not uncommon to have these die after 2 years, which is about as long as the ol' 67w incans. And these 2+ pound modules of plastic, metal and electronics goes straight into the regular garbage can. As "ideal" as LED setups are, they are not perfect yet. In the real world, I think they are worse overall. Some research group should research how much pollution is involved in the manufacture and disposal of the LED "solutions" compared to the standard incan bulb. Everyone only looks at the energy savings or maintenance costs. There's other costs here that people ignore.
Oh, and BTW, the white LEDs in the pedestrian signals are relatively short lived too. Generally the phosphors go yellow or the LED's just end up looking "burned" in prob 2-3 years of service then they fail. JOB SECURITY!!!
Seriously, if we did more solar and wind we could probably increase our lumens if we want, especially when LEDs are putting out 150 lm/W. I do agree on the vehicles though. I wish we would set up our society so we can walk and bike more, and also use public transit more. Basically less spread out living, and less travel overall. The changeover to this type of living would create massive numbers of jobs. The land used to service automobiles is probably the biggest squandering of our finite resources.
