There are many considerations to address when investing in LED street lights. Available products include retrofit kits, new fixtures, “smart” system technology and basic alternatives. Become better informed about the choices and tradeoffs by visiting the resources below.
U.S. DOE’s July, 2014 CALiPER Snapshot: Outdoor Area Lighting Report graphically displays the steady efficacy gains of outdoor area lighting from 2009 to 2014 and displays trends related to color quality, power quality, and correlated color temperature
Sample Model Specifications
The MSSLC Model Specification for LED Roadway Luminaires tutorial guides fixture selection, maximizing system design, and economic performance. In the same vein, the MSSLC Successful Selection of LED Streetlight Luminaires webinar further examines these topics with presenters from major LED street lighting manufacturers Cree and Philips.
The City of Los Angeles shares street lighting vendor requirements in Minimum Requirements for Testing and Evaluation of LED Equipment, aiding other municipalities and utilities in their specification and selection process.
The MSSLC’s Maintenance Practices for LED Street Lights webinar discusses maintenance and reliability of LED streetlights, and advises how to account for these issues when planning and preparing for a transition to LED street lighting.
DesignLights Consortium (DLC) Qualified Products List (QPL): Many entities turn to the DLC QPL to identify commercial LED products that meet standardized performance and efficiency thresholds. The QPL lists approximately 100,000 products from more than 1,200 manufacturers, in 37 product application categories with a web-based database search tool. To search for QPL-listed street lighting, visit the QPL website and select the category for “Outdoor Pole/Arm-Mounted Area and Roadway Luminaires.”
As of December, 2014, there are 60 products listed in this category. Please note, cities and utilities that plan to utilize the list should contact DLC about membership opportunities.
U.S. DOE’s LED Lighting Facts website is recognized as an industry tool for reporting accurate performance about LED products, including roadway lighting. As of early 2015, area and roadway lighting accounts for 18.3 percent of listed products (8,283 total). Buyers and specifiers may use LED Lighting Facts as a basis for verifying product performance, comparing products and identifying the correct product for a given application.
Color Temperature and Human Health
Interest in the effects of color temperature on visibility and human health is on the rise, and researchers are working to better understand the implications so that restrictions, requirements, and recommendations can be made. It is important to better understand the impacts and trade-offs of colored light in night due to the potential effects on alertness, visibility, circadian rhythms and human health.
NEEA’s Seattle LED Adaptive Lighting Study report found that “LED luminaires with a correlated color temperature of 4100K provide the highest detection distance, including statistically significantly better detection distance when compared to High Pressure Sodium luminaires of higher wattage.”
A July 2014 CALiPER Snapshot Report confirms that “Early LED outdoor area lighting products were often known for their higher Correlated Color Temperatures (CCTs). Today, 4000K and 5000K are the most common, and mean CCT has shown a continual downward trend.”
A related consideration is CRI (Color Rendering Index), which measures a light source’s ability to show a range of colors. For reference, the CRI of standard HPS is roughly 21, but for security, IESNA reference RP-20-98 Annex A recommends >60 CRI, and IESNA G-1-03 recommends >50 CRI. LEDs are being produced with much higher CRIs than those of HPS and other fixture types.
U.S. DOE’s Light at Night whitepaper explains that while LED technology holds tremendous potential for energy savings, it is not yet clear whether its spectral characteristics offer vision- and circadian rhythm-related advantages over incumbent light sources.