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Why are these things so $%#^@!! blindingly bright at night?
Wednesday, November 14, 2012

An idea from Science Cafe: Why can't stop lights be dimmer at night?

Good discussion (as always) at last night's Science Cafe, which concerned light pollution and astronomy. It ended with a sidewalk telescope viewing of the moons of Jupiter, just like Gallileo saw them, except we were in front of the lovely Statehouse dome. Not bad.

The best part of these cafes is learning new stuff - well, that and the beer. New ideas (new to me, anyway) have ranged from the importance of road culverts in coping with climate change, to the most significant bias in polling (the bias that people always have an opinion), to the way a wicked smart, well-educated M.D. named meditation as the most important overall tool for fighting chronic pain.

Last night's intriguing idea was a question: Why aren't stop lights dimmable? This came up when an audience member complained about a new stop light in a fairly dark portion of Concord that blasts out light all night. The amount of brightness traffic lights need to be visible in daylight is less than the amount to be visible in dark, so why doesn't it change?

Stop lights are virtually all powered by LEDs now - a change communities have made over the past decade to save electricity - so they could easily be programmed to change their luminosity based on ambient light.

So far as I know, none of them do (although I'm still checking). But what a cool idea - I'd never thought of it. Which is why Science Cafes are so fun.