Since the first decade of the 21st century, the price of white LED light bulbs has dropped dramatically. Now widely available, today's affordable LED
(light-emitting diode) bulbs are six to seven times more efficient and 25 times longer lasting than incandescent bulbs. This affordability and
efficiency have resulted in a surge in both commercial and residential installations, for both interior and exterior applications.
What's good for the wallet isn't necessarily good for the New Mexico night sky, if this technology is applied thoughtlessly in the landscape.
♦ Issue #1: Brightness
A light bulb's efficiency is a measurement of how much light it emits (lumens) compared to how much power it draws (watts). When it comes to big light output
from small power input, LED bulbs are rock stars.
The downside to this energy efficiency is that watt for watt, LED lights are much brighter (have a higher lumen output) than earlier lighting choices.
Why does this matter?
First, because common-sense legislative guidelines on the use of exterior lightingsuch as local lighting ordinances and the
New Mexico Night Sky Protection Actoften express restrictions in terms of watts. These provisions have become meaningless with the arrival of low-watt,
high-lumen LED bulbs. For a given installation, a seemingly benign low-wattage LED light can produce an offensive level of lumens.
Second, because the lower energy use for LED lights may provide an incentive to unnecessarily increase brightness levels and number of exterior fixtures.
"Hey, they don't cost as much to operate, so let's put up a bunch more lights and get more bang for our buck!"
Keep in mind: with LED lights, less is more.
♦ Issue #2: Color
All lighting, even if it appears white, has color content or "color temperature" which is measured in degrees Kelvin. Cool-white LEDs contain far more
blue light than warm-white LEDs which have a yellow or amber tone.
There is mounting scientific evidence that artificial blue light at night is harmful to humans and wildlife and contributes significantly to light pollution.
A link to the International Dark-Sky Association's study on blue-rich white light can be found
Keep in mind: selecting "warm-white" or "soft-white" LEDs with a color temperature of 3000 Kelvin (3000K)
or less is recommended to reduce the risks of blue light exposure at night.
The impact of LED lighting technology on the nighttime landscape is nowhere more evident than in the increasing use of digital billboards, also known as
electronic billboards. Their intense surface brightness and motion effects are distracting to motorists and devastating for the night-sky environment.
A buildup of digital billboards can contribute to visual clutter and community blight.
According to Scenic America:
"Digital billboards, brightly-lit signs with commercial messages that change intermittently every few seconds, appeared along federal
highways around 2005. State transportation officials, charged with controlling outdoor advertising and following the Federal Highway Administration's (FHWA)
longstanding prohibition on intermittent commercial message lighting, turned to FHWA for additional guidance. Under immense pressure from a powerful billboard
lobby to approve the signs, FHWA reversed its long-held position.
Since FHWA reversed its position, the number of digital billboards has risen to nearly 4,000 (nearly a 400% increase) around the country.
Most of these billboards operate along the federal highways regulated under the Highway Beautification Act."
A digital billboard in New Mexico
New Mexicans' view of the night sky was dealt a blow in early 2014, when the State Transportation Commission voted
unanimously to allow electronic billboards along federal highways in New Mexico.
Electronic billboards can also be found within cities and towns in New Mexico, as well as on Native lands.
Everyone who cares about New Mexico's natural beauty, rural character, and small-town flavor (even in our cities), that is, everyone with "pride of place,"
should be concerned about policies that don't take the long view and don't preserve what is uniquely New Mexican. We're not Anywhere, USA, and we
shouldn't ever aspire to look like Anywhere, USA.
Marketing tools that promote New Mexico businesses make a valuable contribution to the economic health of our state, to be sure. But effective tools for
wayfinding and promotion don't require a "visual sledgehammer" approach. What do we want tourists and visitors to New Mexico to remember:
our enchanting vistas or our garish digital billboards?
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Next Section: Impacts of Light Pollution