DOE Publishes GATEWAY Report on Pedestrian Friendly Outdoor Lighting
Although this report was designed and developed for the US market, the insights and recommendations are valid for all countries looking at using LEDs for pedestrian applications. One of the key points raised – uniformity – is a classic example of where LEDs with good optics can provide a safer environment for pedestrians. Reducing dark areas can allow pedestrians to more easily see obstacles, pot-holes, tree roots etc. and thus reduce trips and falls. The report also highlights the need for improved glare control; both disability glare and discomfort glare, and contains some excellent examples.
The U.S. Department of Energy (DOE) has published a new GATEWAY report entitled Pedestrian Friendly Outdoor Lighting. Recognizing that pedestrian lighting has different criteria for success than street and area lighting, GATEWAY followed two pedestrian-scale lighting projects that required multiple mockups – one at Stanford University in California and the other at Chautauqua Institution in upstate New York – to gain insight into what those criteria might be, how they differ from street and area lighting applications, and how solid-state lighting can be better applied in pedestrian applications.
Every outdoor lighting project is different, and tradeoffs between such factors as visual comfort, color, visibility, and efficacy are inevitable. There is no glare metric that works reliably for pedestrian lighting, so full-scale mockups are an important step for gathering feedback from users. The report presents the results of surveys and observations from residents and pedestrians, feedback from facility design and engineering professionals, thoughts and observations from lighting designers, and input from researchers and scientists.
Among the conclusions are that not every neighborhood is suited for pedestrian-friendly approaches, but where communities are receptive, the following may be helpful:
- If luminaire brightness can be controlled, neighborhoods may find lower-lumen-output luminaires and illuminances at the lower end of IES recommendations to be acceptable and even preferred.
- Rather than an array of exposed LEDs, luminaires that spread luminance (“brightness”) over a larger luminous area reduce perception of glare.
- Luminaires with less optical punch and less sharp angular variation in candlepower may provide a softer, more visually comfortable lighted environment.
- Luminaires delivering warmer-color light, usually lower than 4000K correlated color temperature and often below 3000K, may be appropriate for older, more traditional-looking neighborhoods, especially if residents have been used to high-pressure sodium or incandescent outdoor lighting.
The report is available at www.ssl.energy.gov.