Don't be afraid of the dark People have always found darkness frightening, but light may be more dangerous

Sooner or later, when talking about artificial lights and darkness, you come to questions of safety and security. Usually, it’s sooner. In fact, the first question at any presentation about light pollution is bound to be something like, “Yes, so it’s great to see the night sky and everything, but we need lights for safety.” This isn’t actually a question, I realize, and usually the speaker isn’t really asking but rather stating what we have all been taught is fact. But often that statement has a subtext, too, something like what I found on a Colorado website: “less street lighting means more rapes, more assaults, more robberies, and more murders. It is wonderful to be able to see the details of the Crab Nebula from your back yard. It is also wonderful to be able to walk down the street without being attacked by a violent predator.”

You don’t have to look far to find the idea that darkness and danger go together, as do security and light. In Oakland, a city with thirty-seven thousand streetlights, an assistant police chief claims increased lighting levels could help reduce crime because “most of these crooks, when they commit a crime, want to do it in darkness.” In Boston, with sixty-seven thousand streetlights of its own, a Northeastern University criminology professor argues that lights act as “natural surveillance” and can reduce crime by 20 percent. In Los Angeles, home to more than two hundred forty thousand streetlights, the city attributes a 17 percent drop in violent gang-related crimes in the areas surrounding parks to those parks’ having received new lights. And here in Minneapolis the police advise, “Protect your family, property, and neighborhood by turning on your front door and yard lights,” and “Remember: Criminals like the dark, so make sure your yard has lots of light!”

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Clearly, plenty of us have been receiving similar advice — we live in a world that is brighter than ever before, and growing brighter every year. Part of that growth comes from an ever-increasing human population, especially in urban areas. But the amount of light we are using per person is growing as well. In the UK, for example, lighting efficiency has doubled over the past fifty years — but the per capita electricity consumption for lighting increased fourfold over that time. We are choosing to light up more things, and we are lighting those things more brightly.

There’s no doubt light at night can make us safer, from a lighthouse beam guiding ships from rocky coasts to simply enough sidewalk light to keep us from tripping on cracked cement. But increasing numbers of lighting engineers and lighting designers, astronomers and dark sky activists, physicians and lawyers and police now say that often the amount of light we’re using — and how we’re using it — goes far beyond true requirements for safety, and that when it comes to lighting, darkness, and security we tend to assume as common sense ideas that, in truth, are not so black and white.

Foremost among these assumptions is that because some light improves our safety, more light will improve our safety more. It’s an assumption I will hear challenged again and again. As one lighting professional explained, “Too much light would have a negative effect, because if you look into a light, you can’t see anything, you can’t see beyond it.” Gazing from behind his desk, he paused, “You know, a bright enough light in between us and we can’t see each other — and we’re sitting across from each other!”

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The sky over Concord, Massachusetts, this famous town of sixteen thousand about twenty miles west of Boston, reminds me of the sky above my parents’ house near Minneapolis — washed out. (Alan Lewis, whom I have come here to meet, calls it “the great yellow sky.”) Of course, this wasn’t always so. In 1836, for example, Ralph Waldo Emerson wrote of the stars here:

Seen in the streets of cities, how great they are! If the stars

should appear one night in a thousand years, how would men

believe and adore; and preserve for many generations the

remembrance of the city of God which had been shown! But

every night come out these envoys of beauty, and light the

universe with their admonishing smile.

This is almost like reading ancient history — stars, seen from the streets of cities? In this passage from Nature, Emerson looked for a way to make the point that we take nature for granted — we take life for granted — by finding an example of something so commonplace we don’t even see it anymore. What better example than the brilliant starry night over a nineteenth-century Concord lit by oil lamps?

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I didn’t have to visit Concord to know that its sky holds many fewer of Emerson’s “envoys of beauty.” But I wanted to talk with Lewis, to learn more about how too much light could actually act in a negative way. A longtime optometrist and former president of the Illuminating Engineering Society of North America (IESNA), the lighting professionals who have much to say about how we light our world, Alan Lewis has spent the last forty years helping to “educate lighting people about how the visual system operates.”

For example, Lewis says, most streetlights are actually designed in a way that often causes more problems than they solve.

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“Badly designed street lighting, which is probably eighty percent of street lighting, are glare sources,” he explains. “That is, they actually reduce the contrast of things you’re trying to see rather than increase it, because of this disability glare problem that occurs due to scatter in the eye.”

Disability glare from poorly designed streetlights — picture the traditional cobrahead drop-lens fixtures used on most American streets — is the main reason drivers, especially older drivers, have a tough time at night. As we age, proteins in the lens of our eye begin to accumulate, and we lose the transparency we had when we were younger. In the same way that a brand-new windshield is crystal clear but ages over time with accumulated minuscule chips and dings, these proteins reduce the eye’s transparency as they scatter the light coming into the eye. The effect is that instead of going to the retina and focusing, the light is distributed across the retina, casting what Lewis calls “a veiling luminance” that significantly reduces contrast.

To optimize vision, Lewis says, the key is to maximize the contrast — the brightness difference between what you’re trying to see and the background — while minimizing the amount of light going directly from the light source into the eye, because when light goes directly into the eye the greater portion of it is scattered. “You don’t want bright lights coming in from anywhere but the target you’re trying to see,” he says. “I mean any additional source of light out there, like a streetlight shining in your eye or a headlight coming at you or glare sources on a building just makes things harder to see.”

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The second major factor in our seeing well at night (or not) is adaptation, the way our eyes adapt as we move from brighter areas to darker areas. Because of the way our streetlights are usually placed, our eyes constantly have to go back and forth. “If you’re in a place that’s relatively uniformly illuminated by streetlights, then your adaptation remains fairly constant and that’s okay,” Lewis explains. “But what happens is streetlights tend to get dispersed somewhat willy-nilly and so you leave this bright spot and drive into this dark spot but you’re not adapted, and so visibility is actually worse than if you hadn’t had the streetlight there to begin with.” Lewis compares this situation to walking into a movie theater: the way it takes a few moments for your eyes to adapt. “So, as you move from lighted areas to nonlighted areas visibility can actually get worse. In many cases, an equal level of darkness is better than a sporadic light-dark, light-dark area.”

It isn’t only streetlights that cause this problem. The worst offenders, he says, are intensely lit places like gas stations and parking lots. About twenty years ago in America, gas stations began to increase the level of lighting, not for any real safety concerns but for marketing purposes. (“People like light, they’re attracted to it. There’s no question about it,” he says.) “You go in and you fill up under a canopy that was highly lit from a marketing standpoint to attract you, rather than a need for vision,” explains Lewis. “And then you drive out into a dark road and it may be a minute or two before you can readapt to the darkness, which can be very dangerous.”

“Because you might get hit?”

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“Generally you’re okay,” he laughs, “you’re in the car. It’s the other folks who have to worry.”

In other words, it’s for marketing purposes (to get you to stop and buy stuff) that gas stations, shopping malls, and car dealerships are lit so brightly — not, as we might think, primarily for safety. If safety were the primary goal for these establishments, Lewis and others told me, they would be lit much more dimly so that the adaptation and glare problems would be reduced. The problem is that if one business raises its lighting level, the others will feel compelled to as well because by contrast, their establishment will seem dim and therefore less attractive — even closed.

The same scenario holds true for our society in general. As our surroundings grow brighter, we grow used to that level of brightness, and so anything dimmer seems extraordinarily dim, even dark. This is exactly what happened as artificial lighting developed through the ages. The once glorious oil lamps became dim and disgusting with the advent of wonderful gas lighting, which then became smelly and awful and unbearably dim the moment we saw electric light. In other words, once our eyes get used to seeing brighter lights, we must have brighter lights.

* * *

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Overall, the available studies and statistics echo what several people told me, that the term “security lighting” is simply oxymoronic because it assumes a link between security and lighting that research does not support.

In 1977, a U.S. Department of Justice report found that “there is no statistically significant evidence that street lighting impacts the level of crime.” In 1997, a U.S. National Institute of Justice report concluded, “We may speculate that lighting is effective in some places, ineffective in others, and counterproductive in others.” In 2000, the city of Chicago performed a study in which an attempt was made to “reduce crime through improved street and alley lighting.” The city found that “there did not appear to be a suppression effect on crime as a result of increased alley lighting.” In 2002, Australian astronomer Barry Clark conducted an exhaustive review of the research available and concluded that there is “no compelling evidence” that lighting reduces crime and, in fact, “good evidence that darkness reduces crime.”

In late 2008, the Pacific Gas and Electric Company (PG&E) was required by California law to find ways to reduce energy expenditures. In an effort to look into how the reduction of street lighting might do so, company representatives asked for and received an independent review of existing research “relating to any relationship between night-time outdoor lighting and security.” The review found no research that presented sufficient evidence to demonstrate a causal link between night-time lighting and crime” and concluded: “the available results show a mixed picture of positive and negative effects of lighting on crime, most of which are not statistically significant. This suggests either that there is no link between lighting and crime, or that any link is too subtle or complex to have been evident in the data, given the limited size of the studies undertaken.”

As Barry Clark argued in 2002, “Where the justification includes or implies crime prevention,” lighting costs “appear to be a waste of public and private funds.” Updating his review in 2011, he reiterated his earlier findings and wrote, “Given the invalidity of evidence for a beneficial effect and the clear evidence to the contrary, advocating lighting for crime prevention is like advocating use of a flammable liquid to try to put out a fire.”

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These studies have had little effect, however, on the perception that lighting reduces crime at night, and that more light reduces crime further. Perhaps that’s because most of us have never heard of these studies, and so continue to assume a connection between darkness and crime, lighting and security. It doesn’t help that a handful of studies directly or indirectly sponsored by the lighting industry or utility companies persist in claiming that lighting deters crime despite mounting evidence to the contrary. By selling more lights or selling more energy, these companies stand to gain the most wherever the lights are brightest. Widespread ignorance reinforced by questionable research has much to do with this, no doubt.

But there’s something else going on here, too. You get the feeling someone who says “Then send your wife and kids into the darkness and see what happens, or ask a rape victim what they think” isn’t going to be dissuaded by Clark’s study or any other study. Dare to question the idea that we need lots and lots of bright lights for safety and, as Martin Morgan-Taylor of the Campaign for Dark Skies told me in London, “It will often raise quite an aggressive response from people, because it really is the fear of the dark, isn’t it?”

* * *

This is not to say that threats at night don’t exist, or that we have no reason to feel anxious. It’s an especially sad statement about modern Western civilization that women, in particular, are made to feel nervous being out at night.

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“As a woman you’re constantly looking out, trying to maintain your safety,” admits Tiffany Bourelle, a professor at Arizona State University. “I don’t think it’s something anybody can recognize until you’ve been in that situation of fear.”

Bourelle and her husband, Andy, have joined me on Tempe’s “A” mountain to watch the moon rise over greater Phoenix. In the east, the deep dusky purple of Earth’s shadow; in the west, the setting orange sun — the city’s evening humming all around. The planes coming in to PHX pass directly overhead, all polished luminum and engine whine, looking like big white flashlights strung loosely one after another in a long, loose chain stretching east until disappearing on the horizon. Except where they are broken by mountain shards rising from the desert floor, the lights sprawl in every direction to the horizon — the pink-orange of high-pressure sodium streetlights, the sharp green of stoplights, the bright white of empty parking lots. On a distant ridge, a forest of radio towers blinking red.

“If I’m alone in a parking garage late at night,” Bourelle continues, “I have my keys in my hand, with my key in my index finger ready, because that would probably be my only chance. And you guys probably don’t even think about that.”

Listening to her, I think of Rebecca Solnit citing in Wanderlust “the most devastating discovery of my life”: that she had “no real right to life, liberty, and the pursuit of happiness out‑of‑doors.” She describes how in order to walk in the streets she “learned to think like prey, as have most women.” She cites one poll showing two-thirds of American women are afraid to walk alone in their own neighborhoods at night, and another poll reporting half of British women afraid to go out alone after dark and 40 percent “very worried” about being raped.

Yet, as on the university campus, is the danger real or perceived? In their article “The Gendered ‘Nature’ of the Urban Outdoors: Women Negotiating Fear of Violence,” Jennifer K. Wesely and Emily Gaarder studied “the ways that gendered constructions of public space, particularly the wilderness outdoors and urban-proximate areas, inform women’s assessments of vulnerability and fear in these spaces, or their ‘geography of fear.’ ” They found that “violence against women in the private realm far exceeds that in the public sphere,” and “the vast majority of sexual abuse, rape and battering occurs behind closed doors.” They argue, “Countless women are probably denied the healing benefits of wilderness because of the fear of rape behind every bush, around every corner — a fear that every woman in this culture has been taught along with Little Red Riding Hood and the Big Bad Wolf.”

It doesn’t seem to matter what the studies or statistics say — we remember the California college student abducted from a friend’s apartment in Reno and found strangled weeks later on the edge of town, the University of North Carolina student body president kidnapped and killed. The rarity of these crimes doesn’t seem to diminish our fears. We remember the sensational cases, and we are afraid. That forty thousand of us die in traffic accidents each year doesn’t make us afraid of driving, but one rape or murder confirms every fear we have about night’s darkness, and keeps us from going outside at night.

“And it’s nothing that lights can cure,” Bourelle explains. “It’s because there are these stories out here, and every woman knows some woman that’s been attacked, that it doesn’t matter how many lights you put in a place — it’s always going to be dark at night and there’s always going to be shadows, and that one person in a million is going to get raped outside at night. So, there’s really no way to get around it — nighttime makes you feel vulnerable.”

When I hear that phrase I think of Bonnie, a friend in Albuquerque, who committed herself on New Year’s Day a couple of years ago to getting out to see each full moon of the coming year. It wouldn’t be enough to wave at the moon from through the kitchen window, Bonnie had to get out to an area dark enough that she could see her moon shadow. Her long-term relationship had just ended, and she was looking to reconnect with a part of herself she felt she’d given up, and to give herself a positive way of marking the passage of time rather than simply sitting at home waiting to feel better. Whether in the Sandia Mountains east of Albuquerque, the bosque of the city’s North Valley, mountain biking in southern Colorado, or cross-country skiing near Santa Fe, Bonnie made a point of getting out into the dark.

“People were always asking me, ‘Aren’t you afraid?,’ or discouraging me by saying, ‘It’s not safe,’ or, ‘What are you doing out at night?’ There’s this perception that the night is sooooo dangerous. But you’re much more likely to get assaulted in your home at night than you are out in the dark,” she tells me.

“Women are taught to fear,” she continues. “It starts with that mysterious female body stuff that guys are taught to be scared of but, really, women are taught to be scared of as well. We’re taught to hide it, be ashamed of it, to not embrace it.” And part of teaching women to be afraid, Bonnie says, is teaching them to fear being out at night, that bad things are going to happen. “It’s much easier to control people who are scared, who won’t leave the house,” she argues. “It’s this manufactured fear that creates a perception that something bad is going to happen to you.”

The reality, she says, is that as you sit at home watching TV “something bad is happening — you’re getting sick, and you’re missing out.”

Without diminishing the reality of our fears, can we ask what we might be missing? Can we ask what’s lost? What do we lose — women and men alike — when we are so afraid of darkness that we never experience its beauty or understand its value for our world, while allowing our lights to grow ever brighter?

If ever-brighter lights were making us increasingly safe, that might be one thing. But as Eddie Henry, the man responsible for lighting one of London’s toughest boroughs, told me, true safety “is about having the right amount of light and the right type of light and the right color of light for the right place. Rather than, we’re just going to have loads of it!”

Far from being contradictory goals, lighting our nights for safety and controlling light pollution go hand in hand. In fact, one of the most compelling arguments for controlling our lighting at night is that by doing so we will actually make ourselves safer. Said another way, if we are truly concerned about the safety of our wives and daughters and mothers (husbands and sons and fathers), we will understand that light as we use it in most situations makes us less safe by impeding our vision, casting shadows where the “bad guys” can hide, and — perhaps most powerfully — creating the illusion of safety.

Lights can help make us safer, but real safety comes from being aware of our surroundings, making good choices, and not using our natural fear of the dark as an excuse to overlight our nights.

Excerpted from "The End of Night" by Paul Bogard. Copyright © 2013 by Paul Bogard. Reprinted with permission of Little, Brown and Company.