Some of the LED streetlights on the freeways that were installed in 2013-2014 are starting to become really dim. I remember when they were new they were much brighter than the HPS lights in the next section, and now they are only about as bright as 175w /DX mercs. The HPS lights are noticeably brighter now. These I thought would last longer because they have several small diodes spread over a large surface, not 3 high power diodes on a tiny surface (like the new ones they are installing.) What will they do when they become so dim they are unusable?

I noticed that the LED streetlights here actually look very bright, but I have seen a couple of failures where the LED array just periodically flashes.

They all look very bright because the light source emitting area is tiny

I thought that the light on the ground/road was bright.

LEDs that are almost a year old here are green and dim. Lol, so much for high lumen maintenance.

Which LED lights?

Which LED lights?

The ones that are stick-shaped. I can get a picture next week. The difference is quite noticeable.

I have noticed some LED streetlights here getting a bit on the dim side as well. The biggest most noticeable ones are the gross yellowed out LED canopy lights on gas stations installed where MV/MH once were

Generally speaking, if you don't have a light-meter or a lux-meter to measure the light levels, and at the same time write them down, you're talking out of your sinus.

I have documented proof that new LED street-light systems are very typically brighter than the former HPS. Conversly, most parking or lot-lighting LEDs provide less lighting on the lots. In the near future, I'll be comparing the before lux levels to the burned-in levels to see how well the LED systems really perform.

Generally speaking, if you don't have a light-meter or a lux-meter to measure the light levels, and at the same time write them down, you're talking out of your sinus.

I have documented proof that new LED street-light systems are very typically brighter than the former HPS. Conversly, most parking or lot-lighting LEDs provide less lighting on the lots. In the near future, I'll be comparing the before lux levels to the burned-in levels to see how well the LED systems really perform.

Thermally activated degradation of phosphor converted white LEDs is a well known and documented problem, some large bulb manufactures like philips have even opted to dabble in remote phosphor lamps, but people don't understand how a yellow colored light is actually white when it turns on so now they hide the phosphor filters in an attempt to reduce this issue, but the main issue with street lighting is not the technology, because it's 100% doable, it's a lack of understanding the accounting department has of technology they know dollars not LED's, and they are the one's ultimately making the deal and the people who know the issues are the ones instructed to install them and they are all to often not given the opportunity to ask questions or make suggestions... So I would be willing to believe the cheapest fixture will be used and it will have a very short life time and it honestly costs more money upfront to build a high quality fixture that will out preform a tested technology like HID but the long term energy saving will pay off in the end, but don't try to talk to an accountant out of a short term realized gain on the books..   

Just as a quick example you take a RAB fixture and an similar oversea's fixture, just look at the quality of the unit that will give you an idea of how long it will last,

One is machined aluminum and one is cast zinc,
One has nice optics, and full specs available, the other doesn't.
One can show the lumen decrease over time and they base lifespan on IES LM-80 results and TM-21 calculations, the other makes claims of 50,000 to 100,000 hours and that's it.
One is certified by other groups like International Dark Sky Association, COTS, ARRA and others, the other isn't.
One has a realistic warranty the other will dissolve the corporation at the first sign of trouble.
One also costs like 5 times more and, that is the one and only thing only thing an accountant see's $. 

In the end, what do we want? I can only really answer for myself - what do I want? What a multimillion dollar company wants is clearly at odds with what I want. I want long-lasting, smart, economically-efficient, environmentally and astronomically-friendly, non-polluting street-lighting. But I know this is not how the capitalist world works.

Add to the big revenue generating companies creating jobs and light-sources from diodes(!), you have profit motivated distributors and opportunistic little companies & installers - plus the distracted city officials. Is that a recipe for something good or disaster?

Just keep putting Franks Hot Sauce on that .... let me know how it tastes..

But honestly they will end up in the landfill costing the taxpayer more and more money, and right now the lights they are using vs a HPS lamps, the glare is ridiculous not to mention thing's like this, http://www.cbc.ca/news/canada/calgary/seizures-streetlamp-calgary-led-bulb-1.3955106  Really this hit national news but lets keep buying from the lowest bidder, again it's more of the spend a dollar to save a nickel mentality happening ....

This would not be a problem if they just bought real fixtures to start with... I have one over my front door ( led supporters can calm down  now ) it's an R&C  60 watt 4000K Model:>  CLED52N RCL here's the specs https://www.rclighting.ca/product.php?product=CLED52N%20RCL        and I can't get it to cause a seizure, it's almost like they engineered it not to do this, and all it took was to add a two second turn on delay, simplicity at it's finest, and if one driver goes bad they loaded it with two so at the most it would be bright dim and still have a two second delay before repeating, and they use four LED's and made it serviceable if you feel like opening it, LED's are awesome if the engineers are allowed to build a high quality product with out an accountants over site, to bad city planners only buy the junk, guess it'll help  keep people at CBC employed...