What was the cause of death?
Busses rolling over solar panels
In the graveyard, nothing looks busted up or destroyed. It's a very thick concrete substrate, so no flex issues like the other failed roadways. Unless those failed panels are in landfill, not the graveyard. The only other difference is the coating is gravel granules of something that obviously could not compete with a bus tire. Who'd have thought?
Are the yellow LEDs the sort that uses a phosphor? The blue and white LEDs are both blue emitters, so perhaps the intense blue light is affecting the epoxy the same way UV from sunlight breaks down polymers?
SR3 looks like they're using Cree XLamp leds, it looked like amber not "yellow" ? The encapsulation caused trouble.
Cree XLamp Chemical compatibility"Any VOCs present in an SSL system can diffuse into the gas-permeable silicone lens and encapsulants of the LED. Within the molecular structure of these silicone materials, the VOCs will occupy a free space in the interwoven silicone polymer. With subsequent exposure to high photon energy emitted from the LED, along with the heat from the lighting system and the environment, the volatile compounds trapped in the LED's lens or encapsulants can discolor. This discoloration of the trapped VOCs can degrade the light emitted from the LED. This discoloration tends to occur in blue, royal blue and white-light producing LEDs that use blue wavelength LED chips with yellow phosphors for spectrum conversion. This sensitivity to VOCs is not unique to one LED manufacturer but is a known problem for all types of blue, royal blue and white-light LEDs."