LED Street Lights, which are being installed or are on the drawing board for communities all around Australia, use less than half of the electricity of the older lights they generally replace.  That reduces reliance on fossil fuels.  But there's a hidden surprise that may be keeping people up at night.

High-intensity LED streetlights emit unseen blue light that can possibly increase the risk of serious health conditions, including cancer and cardiovascular disease, according to the American Medical Association (AMA).  But these light waves that are invisible to the human eye can disturb sleep rhythms.

Blue-rich LED streetlights operate at a wavelength that most adversely suppresses melatonin during night, tricking your body into reacting as if it were being exposed to bright sunlight at midday.  Some of these LED lamps have five times greater impact on circadian sleep rhythms than old-school street lamps.  The AMA says recent surveys found that brighter residential nighttime lighting is associated with reduced sleep times, dissatisfaction with sleep quality, excessive sleepiness, impaired daytime functioning, and obesity.

Some US communities are adapting to the revelations.  Lake Worth, Florida is installing money- and electricity-saving LED street lights, but the lamps will have a softer, amber glow at a color temperature much cooler than that of the sun.  Phoenix, Arizona is considering a scheme to put standard bright LEDs at intersections and in high traffic areas, with amber-colored lamps in residential neighborhoods.