Internet of Things pioneer Echelon Corporation of Santa Clara, California is currently deploying the first- of-its-kind, so-called “white tunable” connected street lighting in White Bear Lake, a suburb of St. Paul, Minnesota.
Echelon is working with design firm Short Elliott Hendrickson Inc. on the deployment. In addition to controlling the brightness of the streetlights, Echelon says its new Lumewave solution can dynamically regulate the amount of the potentially unhealthy blue light that the outdoor lighting emits. The innovation allows city managers to adjust streetlight color from soothing warm yellow to bright blue-white based on weather, time of day, activity levels, and events.
AMA Recommendations on LED Street Lights
Controlling the color output of the LEDs in the streetlights goes beyond just novelty. Reducing the level of blue emission in LED lighting may offer health and safety benefits according to the American Medical Association (AMA), which issued health and safety related guidelines for street lighting (Ref. Article).
The AMA asserts that conventional white LEDs that use a blue LED and a yellow phosphor light converter to produce white light emit too much blue light. The effects of too much blue emission are not just detrimental to aesthetics and color rendering; The AMA contends that they are detrimental to health and even safety.
Exposure to blue light has been shown to reduce the quality and duration of sleep through the suppression of melatonin as well as disrupt a person’s circadian rhythms. This sleep disturbance can lead to changes in mood in the short term and even an increased risk of obesity in the long-term. Also, older adults especially have been shown to have a reduced ability to discern objects under bluish-white light due to glare. While driving, such glare-induced sight difficulty can become hazardous.
In addition to affecting human health, conventional LED luminaires with high bluish emission can be detrimental to wildlife. Some endangered species such as sea turtles are known to reduce their mating behaviors because of bluish-white lighting.
The AMA’s recommendation is to have street lights with color temperatures no greater than 3000K. The greater the Kelvin color temperature, the more blue light the LED luminaires emit.
On the other hand, using street lights that are too yellow can decrease visibility through a reduction in the color rendering. Dimmer lights inherently reduce visibility as well. The AMA recommendations have been very controversial and are contrary to the advice from driving safety experts which recommend cooler (bluer) color temperatures for improved visibility. The best solution, according to Echelon is to give city managers the ability to change the brightness and color temperature of the streetlights as desired.
The adaptability of the Echelon solution gives city managers the flexibility to weigh the health issues along with the safety issues to meet the community’s needs at any point in time. When there is heavy traffic or events with lots of people, brighter lighting with a bluer (higher) correlated color temperature can be used. Conversely, when traffic is reduced, and fewer people are present, dimmer and lower (yellower) correlated color temperature light can be used.
Benefits of the Connected Control and Monitoring System
The Echelon system called Lumewave is also connected to the Internet. It can collect data from sensors about light levels, as well as occupancy and traffic levels, and it can monitor energy usage for the lights.
The data can be used to make recommendations on the dimming and color-tuning of the light at any given time and can schedule the dimming and color-tuning to maximize energy efficiency or visibility depending on the situation. The data also reveals when a particular light is failing or needs servicing.
The infrastructure that the system creates uses LumInsight® central management system, Echelon’s new CLP 4000 connected lighting controller, and SmartServer™ 2.2 converged universal gateway and its central management system(CMS). The integrated solutions can set color scenes based on manual adjustments, a programmed schedule, or sensor inputs.
“Being the first to try this new technology and see it in action was very rewarding,” said Mark Burch, public works director/city engineer, White Bear Lake. “We could raise the brightness and select a more vivid hue during an evening event. With a scheduled scenario, we could shift the lights in that same area to a warmer hue at 2:00 am when there are rarely park visitors, other than our nocturnal wildlife. We could also program sensors along with the lights to automatically respond to higher foot traffic or certain weather conditions for optimal visibility. The new technology could give us the power to elevate the level of public safety and quality of life across our entire community.”
“Municipalities now have the power to create the perfect environment at any given time,” said Ron Sege, chairman, and CEO, Echelon. “Imagine the improved public safety if all of the streetlights in an area were immediately whiter and brighter when a 911 call was responded to, but otherwise dimmer and more yellow at night for restful sleep. Cities need not compromise safety for comfort or vice versa. Our technology is paving the way for smart cities to improve quality of life, while still achieving energy efficiency and sustainability goals.”