# Red and Green Flashing Traffic Light

**URL:** <https://boards.straightdope.com/t/red-and-green-flashing-traffic-light/206955>\
**Category:** Factual Questions\
**Created:** [October 12, 2003, 3:32am UTC](https://boards.straightdope.com/t/red-and-green-flashing-traffic-light/206955 "2003-10-12T03:32:33Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![peasea](https://avatars.discourse-cdn.com/v4/letter/p/bc79bd/32.png) [@peasea](https://boards.straightdope.com/u/peasea)\
**Post date:** [October 12, 2003, 3:32am UTC](https://boards.straightdope.com/t/red-and-green-flashing-traffic-light/206955/1 "2003-10-12T03:32:33Z")

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So, on my way home tonight, I noticed a traffic light near my home was flashing red and green, alternately. In the past, traffic lights I’ve seen that were malfunctioning either flashed red or yellow, or were off altogether. So, was it just screwed up, or is there some significance I’m ignorant of? My mind keeps going back to that joke about driving through the intersection by hitting the gas, then the brake, then the gas, etc. For the record, I stopped before I went through.

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**Author:** ![peasea](https://avatars.discourse-cdn.com/v4/letter/p/bc79bd/32.png) [@peasea](https://boards.straightdope.com/u/peasea)\
**Post date:** [October 12, 2003, 3:47am UTC](https://boards.straightdope.com/t/red-and-green-flashing-traffic-light/206955/2 "2003-10-12T03:47:31Z")

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Could a mod close this duplicate thread? Thanks.

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**Author:** ![Meeko](https://avatars.discourse-cdn.com/v4/letter/m/e495f1/32.png) [@Meeko](https://boards.straightdope.com/u/Meeko)\
**Post date:** [October 12, 2003, 3:51am UTC](https://boards.straightdope.com/t/red-and-green-flashing-traffic-light/206955/3 "2003-10-12T03:51:06Z")

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If it had three sections, I would assume it has no other significance over a “standard” traffic light. If it had only one section, it might be a variant on the “caution” or perhaps “yeild” light.

I am pretty sure the rule of thumb is to treat malfunctioning lights as a four-way stop.

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**Author:** ![zwede](https://avatars.discourse-cdn.com/v4/letter/z/ac91a4/32.png) [@zwede](https://boards.straightdope.com/u/zwede)\
**Post date:** [October 13, 2003, 4:14pm UTC](https://boards.straightdope.com/t/red-and-green-flashing-traffic-light/206955/4 "2003-10-13T16:14:15Z")

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Sounds either like a weird malfunction or some local ordinance… Can’t think of any reason you would flash red/green.

When traffic lights malfunction they should flash red in one direction (which is treated as a stop sign), and yellow in the other (which is “proceed with caution”). Some lights will flash red in all directions, wich is a 4-way stop.