Many cities across the world are converting streetlights to the LED (Light-Emitting Diode) lamps which helps reduce emissions and the overall carbon footprint. Some health and safety advocates however are concerned about the type of light that LED’s emit.
Most LEDs in street lamps emit a bluish light which is the similar light our phones and tablets emit that experts say interfere with sleep. Studies have shown that this blue light (also emitted by the sun) can suppress melatonin, a hormone that regulates sleep cycles. Not only is this a problem for humans, this is also a problem for all wildlife–especially nocturnal creatures such as bats.
In June, the American Medical Association weighed in with a report that warned that poorly designed LED streetlights can increase glare and disrupt sleep which could lead to chronic health problems such as diabetes and depression. The AMA report recommended that cities use LED lamps that cast a more yellow light and that are fully shielded directing their light downward. The AMA also would like to see cities use lights that have color temperatures of 3000 degrees Kelvin or below. A yellow LED lamp in that range will appear much warmer and emit less glare. More glare at night from lamps causes more shadows which means road users might have a harder time seeing due to the contrast.
LED lamps do not contain as many hazardous materials (such as mercury) as traditional street lamps. LEDs can also be designed to utilize different colors of light. Unfortunately, many cities that converted to LEDs before 2016 put in the higher Kelvin, bluer LEDs but cities converting to LEDs beginning this year have responded to the feedback and are utilizing other LED light colors with a much lower temperatures.
For example, The Wall Street Journal reported in an article this year that Lake Worth, Florida chose the more yellow light LEDs when they decided to convert some 5300 streetlights. The color temperature was measured at 2,700 Kelvins which caused some concern with the Florida DOT which wanted bluer, 4,000 Kelvin LED lamps for major roadways. City officials however, found that the more yellow lights produced the same brightness required by the state DOT. Lake Worth’s city manager Michael Bornstein says the results persuaded the state to allow the town to go with the lower-Kelvin LEDs.
Apparently, the town also chose LEDs with several brightness settings that were used in residential areas. Lake Worth homeowner associations and residents were allowed to choose the setting at the time of installation as well as shields when requested.
The small town of Ouray was one of the first communities in Colorado to install LEDs. City Administrator Patrick Rondinelli says overall citizen feedback has been positive. Ouray, as many other towns and cities, wanted to install LED lights for the cost savings as well as a way to preserve a darker night sky. LEDs cast a more narrow light than traditional lighting which helps when you want to star gaze. However, the more narrow light can obviously make streets darker too. Rondinelli says this is a problem when you have bears walking down side streets. “As our law enforcement are trying to chase bears around and get them out of the community, they have a hard time seeing a lot of that,” said Rondinelli. He adds, “We’ve had some lessons learned along the way. But there’s no regrets.”
Colorado Public Radio reports that more than 10% of outdoor lighting across the country is currently LEDs. Because energy savings can be as much as 50%, many municipalities want to convert. How much of a cost savings and decrease of a carbon footprint can the U.S. expect if all street lamps are converted to LEDs? Non-converted streetlights contain either high-pressure sodium (HPS) or Metal Halide (MH) lamps which typically use 70 to 400 watts of electricity. LED-lit street lamps consume about 35-75% less energy to achieve equal visibility. This means that if all current HPS or MH lamps were replaced by LED lamps, that would be the equivalent of taking 934,066 cars off the road for a year according to the EPA Clean Energy Calculator.
Another cost-saving advantage to LEDs has to do with the inequity of street lighting in many urban neighborhoods and small towns. When cities and small towns can save money switching to LEDs, they can increase the number of streetlights in darker neighborhoods which is safer for residents and all night users of the road.
If you would like to find out more on LED blue lights, Click Here. If your community is thinking of switching to LED Lights, there might be an opportunity to make a difference by sitting on your community’s street light advisory committee. If there is not an advisory committee already in place, perhaps you should talk to your city leaders about helping form one.