The recent American Medical Association policy statement related to high-intensity streetlighting evoked a wide range of responses and opinions from all sides. This development reflects a growing recognition of the unique relationship that humans have with night lighting. While concerns about intensity, glare and light trespass are not new, the rapid transformation to LED streetlighting is prompting new attention to these topics.
Echelon has recent and substantial experience with these emerging dynamics, having deployed two complete “border-to-border” solutions in the U.S., in Cambridge Massachusetts and Bellingham Washington. In both cities, the installation of high-intensity LED lighting plus intelligent networked control has provided a unique opportunity to collaborate on the development of new best practices when faced with resident feedback about the intensity and color of new LED streetlights or the at-times undesirable light trespass into living spaces.
Our experience in these two cities with the state of current adaptive control technology is that solutions currently exist to satisfactorily address many of these concerns on a dynamic, real-time basis. Adaptive control technology refers to the ability to dynamically adjust light levels, either pole-by-pole or by groups or zones of lighting. Such light level adjustment can occur throughout a nighttime cycle based on a schedule or in real time in response to an environmental trigger such as motion. Using Echelon’s technology solutions, city managers can balance energy savings, safety, and citizen comfort on a dynamic basis.
For instance, in Cambridge, specific neighborhood profiles have been created that turn streetlighting on at 70% or 50% of full output, depending on the characteristics of the neighborhood. Further light level adjustments can occur throughout the nighttime cycle, such as dimming light levels to as low as 35% and then ramping back up to higher levels in the pre-dawn hours when vehicular traffic increases. This provides responsiveness to suggestions such as the AMA’s observation that “consideration should be given to utilizing the ability of LED lighting to be dimmed for off-peak time periods.”
Not only does this dynamic control capability give municipalities more flexibility in responding to resident feedback swiftly, it can be continuously modified from a web-based dashboard that minimizes deployment of valuable public works resources.
For more information on this topic, the following resources can be of great value:
- SSL Postings, U.S. Department of Energy. “LED Street Lighting,” June 21, 2016.
- U.S. Department of Energy, Energy Efficiency & Renewable Energy Program, Solid-State Lighting. “True Colors. LEDs and the relationship between CCT, CRI, optical safety, material degradation, and photobiological stimulation.”
- Illuminating Engineering Society (IES) IES RP-33-14. Lighting for Exterior Environments. July 2014. Available from the IES bookstore at http://www.ies.org/store/