US Streetlights Are Turning Purple

Cause of the Purple Streetlights

• Strong consensus that the purple color is a failure mode: the phosphor layer on “white” LEDs is degrading/delaminating, exposing the underlying blue/blue‑violet LED.
• Several references to teardowns show cracked or missing phosphor-on-silicone layers on the LED package, likely related to thermal cycling and harsh outdoor conditions.
• Some note that the article oversimplifies phosphor behavior and treats it as narrowband when it’s usually broadband.
• A linked technical article and videos are cited as more authoritative than the popular piece.

LED vs Sodium Vapor: Color, Vision, and Safety

• Debate over whether LED “white” is better than sodium’s orange/yellow:
  • Some find sodium’s monochromatic orange extremely ugly and poor for color rendering.
  • Others prefer sodium’s softer, less glaring light and better comfort in bad weather.
• Narrow-band sodium has benefits for astrophotography and filtering light pollution.
• Discussion of visual performance:
  • Blue-ish light may improve peripheral detection but reduce central contrast.
  • Some argue that higher contrast or brightness isn’t always safer due to glare and uneven illumination.

Design Quality, Cost Cutting, and Vendor Issues

• Many attribute failures to cost-cutting: overdriven LEDs, poor thermal design, cheap phosphor/silicone, and low-end drivers.
• Mention that U.S. municipal lighting is highly concentrated with a small number of vendors; one major manufacturer reportedly acknowledged a phosphor defect and launched a large warranty program, but replacements lag.
• Some note that governments often factor in labor and replacement costs and avoid the absolute cheapest products, whereas private lots tend not to.

Human Comfort, Circadian Rhythm, and Aesthetics

• Concerns about harsh, cool-white LED streetlights disrupting circadian rhythms and being visually tiring, especially compared to warmer legacy lighting.
• Others say high‑CRI, warm LEDs can be as pleasant as incandescent, but are rarely chosen for cost reasons.
• Several people dislike the sharp, high-contrast shadows and perceived flicker of many LED installations.

Public Perception and Misconceptions

• Many anecdotes of people assuming purple lights are intentional (for bats, anti-drug measures, etc.) rather than a defect.
• Some see this as evidence of how quickly people jump to conspiracy explanations over mundane engineering failures.

Broader LED Reliability Experiences

• Mixed experiences in homes: some report decade-long reliability from quality brands; others see frequent failures, color shifts, and flicker from cheap products.
• Discussion that LEDs themselves are robust, but drivers, cooling, and mains compatibility (voltage, transformers) are common weak points.

Attitudes Toward Purple and LED Lighting

• Most find purple streetlights disorienting, unsafe, or nightclub-like; a minority enjoy the sci‑fi/retro aesthetic.
• Underlying theme: better upfront design (including failure modes, spectrum, and intensity) could have avoided both the failures and much of the backlash.