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Why are traffic lights red, green and yellow?

September 1st, 2008

“On a traffic light green means go and yellow means yield, but on a banana it’s just the opposite. Green means hold on, yellow means go ahead, and red means where the hell did you get that banana at…”

Quote on traffic lights from Mitch Hedberg, rather true imagine having a red banana? You would scare the heck out of people. We see these traffic lights daily, have you ever wondered why are the traffic lights red, green and yellow? Why not blue, pink and black? There has to be a history behind it or some logic behind the overall color structure? Most of us, do not care because after all we are all ignorant in a sense. Today’s post will look at this puzzling question and answer it.

As many of you know, colors have symbols and meanings, not just in our modern day life back in ancient times as well although we did not have all the colors that we have today, there were the basic colors. Before we dive into the answer to this puzzling question lets look at the meaning, symbolism and psychology behind the these three colors (red, green and yellow).

Source – Color Meaning, Symbolism and Psychology

Color Red

Red has more personal associations than any other color. Recognized as a stimulant red is inherently exciting and the amount of red is directly related to the level of energy perceived. Red draws attention and a keen use of red as an accent can immediately focus attention on a particular element. How the color red effects us mentally and physically * Increases enthusiasm * Stimulates energy * Encourages action and confidence * A sense of protection from fears and anxiety

Color Green

Green occupies more space in the spectrum visible to the human eye and is second only to blue as a favorite color. Green is the pervasive color in the natural world that is an ideal backdrop in interior design because we are so used to seeing it everywhere. The natural greens, from forest to lime, are seen as tranquil and refreshing, with a natural balance of cool and warm (blue and yellow) undertones. Green is considered the color of peace and ecology. However, there is an “institutional” side to green, associated with illness or Government-issued that conjure up negative emotions as do the “slimy” or bilious greens. How the color green effects us physically and mentally * Soothing * Relaxing mentally as well as physically * Helps alleviate depression, nervousness and anxiety * Offers a sense of renewal, self-control and harmony

Color Yellow

Yellow shines with optimism, enlightenment, and happiness. Shades of golden yellow carry the promise of a positive future. Yellow will advance from surrounding colors and instill optimism and energy as well as spark creative thoughts. How the color yellow effects us mentally and physically * Mentally stimulating * Stimulates the nervous system * Activates memory * Encourages communication

Now we have a good understanding of colors and now the answer for the puzzling question will make a lot more sense than if I were to just answer the question.

Traffic lights system actually comes from the railway system. Trains required an advance caution to prevent deadly accidents and collisions. Engineers first choice was red for stop, which makes sense if we read the symbolism of the color red. Color red had represented danger for thousands of years.  Engineers tried using green and red lights in way that, Green was for caution, red for stop and clear for go but soon the engineers realized that the sunlight reflecting off clear lights gave false signals. Thus they came up with the ingenious idea of having yellow for caution and making green for go.

And that is why today, we have traffic lights with the color red, green and yellow.

Fun fact, it is said that lantern was used as a first traffic light. But it could not handle the winds and soon the light system came.

  1. Cureless
    September 1st, 2008 at 12:06 | #1

    wow that is nice stuff . I knew the color symbolism part how red is danger it could be associated with blood.

    And how it was railway system , now its used everywhere.

  2. Jamie
    September 1st, 2008 at 14:10 | #2

    Nice stuff again WOOOO WOOOO.

    If i would chose the colors i would put pink XD

  3. Jeff
    September 1st, 2008 at 14:11 | #3

    Jamie pink is hard to see i would put brown haha cause i love them brownies.

  4. Ratchan
    September 1st, 2008 at 14:12 | #4

    Ausite diez van gor hof.

    Hmm this is american shit.

  5. Angie
    September 1st, 2008 at 14:14 | #5

    Yup , i learned this in a class i dont remember where thought.

  6. King
    September 1st, 2008 at 15:13 | #6

    I dont wait for the green light thats a waste of time.

  7. John huckleman
    September 1st, 2008 at 15:24 | #7

    Sorry posted by accident.

  8. Xray man
    September 1st, 2008 at 15:26 | #8

    WTF i want more stats.

  9. Darren Whittown
    September 1st, 2008 at 17:02 | #9

    Pretty good and useless info for mah brain.

  10. Jason B
    September 1st, 2008 at 17:03 | #10

    yo bro this is the shit right here…

    I never knew there was a reason behind all this

  11. Chris Harris
    September 1st, 2008 at 17:06 | #11

    Wow god… this sun thing was obvious , the reflection changes the colors.

  12. Thedorie
    September 1st, 2008 at 17:17 | #12

    Ok i guess not something i d say to everyone but good for myself.

  13. Kevin
    September 2nd, 2008 at 12:40 | #13

    When traveling in Europe I noticed that in some countries traffic lights turn yellow right before they are about to turn green. This makes so much better sense to me! I don’t know why we don’t do this here in the U.S. Wouldn’t you like to know that your light is about to turn green?

  14. September 2nd, 2008 at 23:30 | #14

    if i concentrate i can hear distinct tones for each of the corresponding colored lights.

  15. Sridharan PVM
    August 30th, 2009 at 03:02 | #15

    Good one -really .

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