# Street lights - why orange?

**URL:** <https://boards.straightdope.com/t/street-lights-why-orange/145821>\
**Category:** Factual Questions\
**Created:** [December 31, 2002, 4:51am UTC](https://boards.straightdope.com/t/street-lights-why-orange/145821 "2002-12-31T04:51:01Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![zia\_nova](https://avatars.discourse-cdn.com/v4/letter/z/bc79bd/32.png) [@zia\_nova](https://boards.straightdope.com/u/zia_nova)\
**Post date:** [December 31, 2002, 4:51am UTC](https://boards.straightdope.com/t/street-lights-why-orange/145821/1 "2002-12-31T04:51:01Z")

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I’m sure this has been asked but I searched and couldn’t find anything that helped me. So if I’m repeating past posts, sorry.

Why are street lights that yucky orange colour? Who decided they should be? Of all the colours in the world he had to choose from, why ‘orrible orange’ and why can’t they change it?!

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**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\
**Post date:** [December 31, 2002, 5:00am UTC](https://boards.straightdope.com/t/street-lights-why-orange/145821/2 "2002-12-31T05:00:31Z")

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[Outdoor Lighting: Mercury Vapor or High Pressure Sodium?](http://www.human.cornell.edu/dea/extension/docs/sum99/outlight.htm)

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**Author:** ![andy\_fl](https://avatars.discourse-cdn.com/v4/letter/a/49beb7/32.png) [@andy\_fl](https://boards.straightdope.com/u/andy_fl)\
**Post date:** [December 31, 2002, 5:01am UTC](https://boards.straightdope.com/t/street-lights-why-orange/145821/3 "2002-12-31T05:01:58Z")

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Those are Sodium Vapor Lamps. The color characteristic frquency of Sodium Atoms. Its used because it consumes less energy.

From [here](http://www.howstuffworks.com/question387.htm)

> [@](#):
>
> _Mercury and sodium vapor lamps produce light using a technique similar to that used in fluorescent lamps. In fluorescent lamps a low-pressure mercury vapor produces lots of ultraviolet light that excites a phosphor coating the tube. In the case of mercury vapor lamps, it is a high-pressure gas, the distance between the electrodes is very short and the light is produced directly without the need for the phosphor_

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**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\
**Post date:** [December 31, 2002, 5:03am UTC](https://boards.straightdope.com/t/street-lights-why-orange/145821/4 "2002-12-31T05:03:41Z")

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[Why different bulbs cast different colored light](http://americanhistory.si.edu/lighting/webnote6.htm) with photos and graphs.

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**Author:** ![zia\_nova](https://avatars.discourse-cdn.com/v4/letter/z/bc79bd/32.png) [@zia\_nova](https://boards.straightdope.com/u/zia_nova)\
**Post date:** [December 31, 2002, 5:08am UTC](https://boards.straightdope.com/t/street-lights-why-orange/145821/5 "2002-12-31T05:08:43Z")

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ah-ha. Links. And such quick replies.  
Thanks guys!