A lighting designer found brighter streetlights actually blind CCTV cameras too

A lighting designer's odd finding: the brighter the streetlight, the worse the camera sees

Simon Thorp, a lighting designer working across London's public spaces, has a finding that undercuts the entire justification cities use for blasting streets with light: modern CCTV cameras perform “pretty great” even at low-light levels, while harsh, glaring light actually makes it harder for both eyes and digital sensors to see clearly. IEEE Spectrum's account of the LED transition builds its case around exactly this kind of counterintuitive result: the technology that was supposed to fix outdoor lighting has, in most installations, made light pollution worse, not better.

The scale of the problem is not small. LED streetlights went from a rarity a decade ago to covering more than half of US streetlights by 2019, on track for 90 percent by 2030, installed almost entirely on the promise that they use up to 90 percent less energy than the incandescent and sodium bulbs they replaced. Global light pollution keeps rising anyway, by nearly 10 percent a year, because cheap white LEDs pack far more blue light into their spectrum than the sodium bulbs they replaced, and blue light scatters across the sky more efficiently than any other color. It's a clean case of the Jevons paradox: efficiency gains, spent on more light instead of less.

Ruskin Hartley, CEO of DarkSky International, distills the fix into five words: useful, targeted, low-level, controlled, warm-colored. Warm 2,700K bulbs disrupt circadian rhythms far less than the cool 4,000-6,500K white light most cities default to. Blue-heavy light suppresses melatonin, with knock-on links to obesity and type 2 diabetes. Phoenix converted 100,000 streetlamps to warmer output in 2020. France went further: a 2019 law bans light aimed above the horizon and forces shopfronts dark after 1 a.m., and the country has managed to cut its light pollution even as the rest of the world's kept climbing.

None of this requires giving up brightness where it's actually needed. Paul Drosihn, general manager of the DALI Alliance, points to networked digital dimming: lights that brighten during rush hour and fade to near-nothing at 2 a.m., all controlled in software rather than rewired by hand, which also cuts repair callouts from three visits to one. Chloé Beaudet, a researcher at Université Paris-Saclay, found that city residents actually support dimming policies once they're explained; the resistance isn't public opinion, it's inertia in how contracts get written and bulbs get bought.

The thread's proof that most cities do this backwards anyway

The 161-comment discussion mostly confirmed the article's central worry: intentions are warm, installations are cold.

"I once lived in a city that had replaced street lights that cast light in a circle with modernised ones that cast a sharply delimited rectangle of light on the road, and didn't waste light in other directions. … Only after the city had rolled out thousands of these lights did someone notice the footpaths were now much darker. And also the footpaths were quite uneven, due to the trees' roots - a problem the lights had previously been keeping under control. It's now common, in winter, to see groups jogging on the road." — a reader whose own city botched a similar streetlight swap

Another reader described a nearly identical failure closer to home:

"Our city recently went on a crusade on replacing all of the high pressure sodium bulbs with LEDs, with the justifications of driving safety and energy savings. I agree that these are important, but the LED bulbs they chose are actively hostile to homes and pedestrians. They are blinding. You can't look at them. I have one outside our house in the main viewing angle and we need to close our shades as soon as they are turned on." — a resident in the thread

A few commenters pushed back on the article's own choices, not just the industry's. One noticed how casually the piece treated surveillance as an argument for keeping streets bright:

"That's a weird thing to include. That sounds like an argument for more aggressive lights. I didn't expect to see a “think of the surveillance system”" — a software contractor in the thread

Proof it's not just theory: a New Zealand region already dimmed its skies back

Not every story in the thread was a cautionary one.

"In recent years the effort has moved into the cities. Interestingly people who live on hills, overlooking the suburbs, complain the lovely view of the sparkling streets was going dark! But not only does it preserve the stars it is much cheaper, so not going back." — a reader in New Zealand's South Island, where his region already dimmed its streets

His region started in Tekapo, a rural area built around protecting existing observatories, before expanding the dimming program into its cities: the same sequence IEEE Spectrum describes for France, just running a few years further along.

What the thread adds to the article's case is the missing variable: cost. Every reader who described a working warm-and-dimmed system also mentioned it came in cheaper, not more expensive, than the harsh version it replaced. The obstacle was never engineering or budget: it's that "install the brightest, whitest light for the lowest sticker price" is still the default spec on most city contracts, and nobody's rewritten it.