Red, yellow and green: why these colors were chosen for the traffic light. How the traffic light appeared and why yellow, green and red were chosen for it

Why does the traffic light have exactly these three colors - red, yellow and green !?

Why did the choice of colors for traffic lights fall on red, yellow and green? It is generally accepted that this is due to two main reasons. One of them is in the field of physics, the other in the field of human psychophysiology.

Let's first look at the history of traffic lights, and so:

The inventor of the first electric traffic light is Lester Wire from Salt Lake City (Utah, USA). In 1912, he developed, but unfortunately did not patent his own, a traffic light with two round electrical signals, red and green.

On August 5, 1914, in Cleveland, Ohio, USA, the American Traffic Signal Company installed four electric traffic lights designed by James Hoag at the intersection of 105th Street and Euclid Avenue. They had a red and green signal and, switching, emitted a sound signal. The system was controlled by a police officer sitting in a glass booth at an intersection. Traffic lights set traffic rules similar to those adopted in modern America: a right turn was carried out at any time in the absence of interference, and a left turn was carried out at a green signal around the center of the intersection.

And only in 1918, to the two colors of the traffic light - red and green, another color was added - yellow. Tricolor yellow traffic lights have been installed in Detroit and New York.

James Hough's traffic light system (drawing from the patent)

In Europe, similar traffic lights were first installed in 1922 in Paris at the intersection of Rue de Rivoli and Sevastopol Boulevard. Still in Hamburg on the Stephansplatz square, as well as in England - in 1927 in the city of Wolverhampton.

In the USSR, the first traffic light was installed on January 15, 1930 in Leningrad at the intersection of 25 October and Volodarsky avenues, now Nevsky and Liteiny avenues. And the first traffic light in Moscow appeared on December 30 of the same year at the corner of Petrovka and Kuznetsky Most streets.

In connection with the history of the traffic light, the name of the American inventor Garrett Morgan is often mentioned, who patented the traffic light of the original design in 1922. There is a persistent myth about Morgan's great influence on the development of traffic lights, but in reality he is only one of many inventors of various traffic lights at the beginning of the 20th century.

Well, why did Lester Weir choose these colors? Perhaps in the first place he was guided by the psychophysiological perception of color by a person - red as a danger and prohibition, and green as calmness and resolution. But is this really so, let's turn again to the history and research of many inventors of the first traffic lights and their observations of the propagation of light, of a different spectrum, in the air.

Let's take a look at all the factors by which these three colors were chosen - red, yellow and green!

PSYCHOPHYSIOLOGY.

As already mentioned, the first is psychophysiology - colors have different effects on their expressiveness.

In many publications on this topic, and on the Internet, assertions are published that the red color often in nature for many living beings is a signal of a very close danger. This is very strange - because scientists have proven that most animals are color blind and do not distinguish colors. And further - as these "publications" claim that the opportunity to run over a pedestrian is a dangerous situation for two participants on the road and a red signal excites the nerve centers of the driver and pedestrian, indicating that there is an imminent danger! Perhaps, but still, let's explore this topic further.

Further, it is argued that it is these three colors that are most well perceived by the human eye in terms of their physical parameters and the wavelength inherent in them. Yes, this is exactly so, because these three colors have the longest, so to speak, wavelength. Here's a look at the visible spectrum of colors.

From the above figure, we see that ours - red, yellow and green colors are at the very beginning of the visible spectrum, respectively, have the longest wavelength.

Next, we will tell you what we brought this example, but for now we will continue to consider further explanations of what the publications write. Further, it is explained to us that the sensation of the chromaticity of red and green signals, as prohibiting and prohibiting movement, should be clearly identified without the possibility of error. What is observed. Even color blind people who cannot distinguish colors in terms of shades of gray can accurately respond to the color of a traffic light red or green! Hmm! Why, then, is it forbidden to have a driver's license with such a disease !? - the question immediately arises! But the articles are quickly rehabilitated and explain it in such a way that - “… although this definition of a person's physical defect is greatly weakened. Therefore, there is a ban on driving with such a disease ... ".

Well, and the following explanation about the green color: “... it should be clearly understood that a person's vision to light of different wavelengths of light reacts with greater or lesser sensitivity. The choice of resolving green light is due to the maximum proximity of this color to the level of the most clearly perceived part of the spectrum. It is visible in contrast to other traffic light colors from the greatest possible distance, because the highest sensitivity of the eye is at 555 nm. And the perception of green, which has a range of values \u200b\u200bof 500-550 nm of the spectrum, at different times of the day does not fall below 0.5 of the maximum sensitivity value, both during daytime and twilight observation ... "

Here we disagree a little and explain why we gave the above example with the visible color spectrum.

PHYSICS OF COLOR. DIFFUSION.

In fact, the colors green, yellow and red were chosen in the design of traffic lights in part because red is perceived as danger, yellow as concentration, and green as resolution. The question was in the range of visibility in different weather conditions. And such a concept as light scattering was taken into account.

Such a concept as Rayleigh scattering was taken into account. What it is!? This is elastic scattering of light or other electromagnetic radiation by objects or surfaces much smaller than the wavelength of the incident light. This can often occur on transparent solids and liquids, but is more common in gases. This type of scattering occurs in blue sky rays during the day. Rayleigh scattering is inversely proportional to the fourth power of wavelength, which means that shorter wavelengths of blue light will be scattered more strongly than longer wavelengths (such as green and red). Which was taken into account. This dependence was deduced by the British physicist John Rayleigh back in 1871. All inventors of traffic lights based their choice on this dependence, because we know the air contains droplets of suspended liquid both during the day and at night. For this reason, the Rayleigh scattering was taken into account.

Those. everything is much simpler than the perception of colors. It's all about the physics of color. From the figure, we can see that the red, yellow and green colors are scattered less than other colors. From this we can conclude that in bad weather - fog or rain, the red color of the traffic light will be visible farthest, yellow will dissipate a little faster, but green will be visible at a shorter distance than its two "older brothers". Personally, as a person who is simply interested in everything, I was very surprised by many publications on the Internet that I initially read while preparing this article, claiming that it is the green color that will be seen farthest! But based on the physics of color and the dependence of John Rayleigh, we see that it will be quite the opposite!

So the reason for choosing these three traffic light colors turns out to be much more mundane than others imagine - namely, in the properties of different colors and their dispersion in the air! People were worried about road safety and the visibility of traffic lights at a longer distance under various weather conditions - be it clear weather, fog or rain (which England is rich in), snow, hail and other weather phenomena, the light from the traffic controller should be seen as far away as possible!

I think if the blue color - the color of calmness, scattered the worst of all and it could be seen at a farther distance, then the choice would fall on this color, and not on red. And here the formula "color danger" would not fit.

For example, if you painted “anger” in a yellow traffic light, then you have noticed that a dull irritation is growing inside you and you are about to break into an open expression of anger or a cry.

Green traffic light emotion Is a signal that you are okay with this emotion. The degree of its manifestation is minimal or tends to zero.

If you paint "anger" in a green traffic light, it means you are balanced and calm for today.

Color your emotions and stress in 3 traffic light colors.

Try the 7 words below and color them in the 3 emotional traffic light colors.

What color of traffic lights prevails and is on in your life now?

Green? Yellow and Green? Yellow? Red and Yellow or Red?

The scale of human emotional states.

View traffic light colors distributed between these 7 emotions - what color is your emotional state ?

Are your emotions going through the roof or are they normal?

On what scale is the arrow of today's emotions frozen?

Arrow on the green scale of emotional state.

In your assessment of emotions, green prevails.

Most words show green traffic lights. Everything is fine. You don't need to worry.

Arrow on the orange emotional state scale.

In your assessment of emotions, red and yellow are roughly equal.

It is worth considering if 2-3 out of 7 words are red - this is a signal of danger, even if the rest of your emotions are shining with a green traffic light.
Perhaps you have recently witnessed a disaster or experienced a strong one.
Moderate stress is present in all areas of life. You are going through a divorce, dismissal or change of residence.

Arrow on the red scale of emotional state.

Most of your emotions are in the red spectrum of traffic lights.

What sector of the emotional state scale is your arrow on? Share!

What psychological help do you need?

Depending on which color of the scale of the emotional state your arrow points to, you need one or another type of psychological help.

If your arrow points to green - You are fine and do not need psychological help. On the contrary, you yourself can safely ask for emotional support.

If your arrow is in the blue spectrum - You can still handle it yourself. Seek support from friends and family. Relax, get out into nature, sleep an extra couple of hours.

If your arrow is in the yellow or orange spectrum - You already need a different kind of psychological support than the support of a friend. For these colors, a good one, prepared by a professional psychologist, is suitable.

For instance, an audio course of the psychologist of happiness "Healing the Soul" which contains several meditations to support and heal your Inner Child. You can do it if you do these audio visualizations with the help of a psychologist right now.

If your arrow is in the red spectrum - For the self-therapy course, it is necessary to consult a psychologist who can work with emotional problems and stressful conditions.

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Today it is very difficult to imagine traffic rules without the main tool for ordering traffic, which is a traffic light. It is designed to regulate and facilitate both car and pedestrian traffic. There are different traffic signals, depending on their function. Although they are similar to each other, they have certain nuances that must be remembered.

Traffic light: definition

A traffic light is an optical signaling device that is designed to regulate the movement of cars, bicycles and other vehicles, as well as pedestrians. It is used in all world states without exception.

Interesting! Previously, there was no green light in traffic lights in Japan. It was replaced by blue. But scientists have proven that green is more acceptable to human eyes.

Types of traffic lights

The most common are three-color traffic lights with round signals: red, yellow and green. Traffic rules in some countries suggest the use of orange traffic signals instead of yellow ones. Signals can be positioned both vertically and horizontally. If no other special traffic lights or additional sections are provided, then they regulate the movement of all types of transport, as well as pedestrians. Next, we will look at the different types of traffic lights, from everyday to special ones.

Classic three-section traffic light

Such a traffic light has, as a rule, three colors, arranged in order: red, yellow, green - from top to bottom or from left to right. Such traffic lights are installed at intersections. They are designed for the simultaneous passage of all types of transport in all directions permitted by traffic rules. They are also installed at regulated pedestrian crossings located between intersections. It is allowed to install such a traffic light at a railway crossing in populated areas, at the intersection of a road with tram tracks, in front of a bicycle path and a carriageway.They can also be seen where there is a narrowing of the carriageway to allow oncoming traffic alternately.

Interesting fact!The first three-section traffic light was installed in Detroit in 1920.

Two-piece

Traffic lights with two sections are used to regulate the flow of traffic on the territories of industrial enterprises and organizations, as well as during the narrowing of the carriageway to organize a single-lane reverse traffic flow.

Single-section traffic light with yellow light

This one-color traffic light is found at unregulated intersections and pedestrian crossings.

Traffic lights with additional section

Traffic lights can be equipped with additional sectional sections with arrows or arrow contours. They regulate the movement of traffic in one direction or another. Such traffic lights work, according to traffic rules, as follows: the outline of the arrows on all signals of a conventional three-color traffic light means that its action extends only in one indicated direction.

An additional section of the traffic light with a green arrow on a black background, according to traffic rules, allows passage, but does not provide advantages during the crossing. Sometimes you can find an always burning green signal, which is made in the form of a plate with a solid green arrow. This means, according to the traffic rules, that the turn is allowed, despite the prohibitory traffic signals.

Such traffic lights are installed in places where it is necessary to organize conflict-free traffic at intersections. If a green light comes on at one of these traffic lights, then, crossing the intersection, you can not give way. To avoid emergencies, personal traffic lights are placed above each lane, which show the direction of movement that is allowed from a particular lane.

Reversible traffic lights

To regulate traffic on the lanes of the carriageway, reversible traffic lights are used.These are special strip control knobs. At such traffic lights, from two to three signals can be placed: a red signal in the form of the letter "X" prohibits movement on a specific lane. The green arrow pointing down, on the contrary, allows movement. A diagonal yellow arrow signals that the lane driving mode has been changed, and shows in which direction you need to leave it.

Traffic lights to control traffic across a pedestrian crossing

Usually such traffic lights have only two types of signals: the first one permits, the second one prohibits.As a rule, they correspond to green and red. The signals themselves can be of different shapes. They are often depicted as a stylized silhouette of a person: standing red and walking green. For example, in America, the prohibitory signal is carried out in the form of a raised red palm, meaning “stop”. Sometimes the inscriptions are used: red "stop" and green "walk". In other countries, respectively, in other languages.

Traffic lights with automatic switching are installed on highways with busy traffic. But there are times when you can switch the traffic light by pressing a special button, which allows you to cross the road for a certain time. For convenience, modern traffic lights are equipped with a digital countdown display. For blind people, sound devices are mounted in traffic lights.

To regulate the movement of trams

Tram traffic lights are usually placed in front of areas with limited visibility, long ups and downs, at the tram depot and in front of switches. Tram traffic signals are of two types: green and red. They are installed either to the right of the tracks, or they are hung in the center above the contact wire. Basically, such traffic lights notify tram drivers whether the path is busy further or not. They do not regulate the movement of other vehicles and are purely individual. Their work is built automatically.

Traffic lights: driving rules

Round light signals mean the following: a static green signal permits the movement of vehicles or pedestrians, and a flashing green signal of a traffic light means that a prohibitory signal will light up soon, but while movement is allowed.

Interesting fact!Residents of large cities generally spend about six months of their lives waiting for a permitting traffic signal.

What does a yellow traffic light mean? It warns that the prohibiting signal will be replaced by a permissive one or vice versa, and prohibits movement for the duration of its action. A flashing yellow traffic light means that the section of the road on which this traffic light is located is not regulated. If it is located at an intersection and operates in this mode, then the intersection is unregulated. Drivers are guided by those articles of the traffic rules, which stipulate the passage of unregulated intersections. A static and flashing red signal prohibits movement in any direction.

Red and yellow traffic light signals lit at the same time indicate that it is forbidden to move further, and the green light will light up soon. The white-moon traffic signal informs that the signaling is in order and you can continue driving. Such traffic lights are installed on tram and railway tracks.

Traffic light signals, which look like arrows, mean the following: red, yellow and green arrows mean the same as round signals, only they act in a certain direction. An arrow that points to the left also permits a U-turn, if this does not prohibit the corresponding traffic sign next in priority.

The green arrow of the additional section has a similar meaning. If this signal is turned off, or the red outline is on, it means that movement in this direction is prohibited. If the main green signal has a black outline arrow, then this means that there are other directions of movement besides those indicated by the additional section.

What is more important: a sign, traffic light or markings?

Traffic rules imply the following priority: the main one is the traffic controller, then the traffic light, then the sign and then the marking. The signals of the traffic controller are more important than traffic signals and the requirements of road signs. They are mandatory. All traffic lights, except for the flashing yellow, are more significant than traffic signs. All road users are obliged to follow the instructions of the traffic controller, even if they contradict traffic lights, signs and markings.

The German capital has a traffic light with thirteen signals. It is not so easy to immediately understand his testimony.

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The world's first traffic light appeared in London near the Houses of Parliament on December 10, 1868. It was intended for carts that had to stop in order to let pedestrians pass: an arrow raised up prohibited movement, and an arrow located at an angle of 45 ° indicated that you need to drive with caution. And at night, a gas lantern served as a traffic light, which was rotated by hand: while the green light, like today, allowed passage, and the red one prohibited.

website decided to figure out why the traffic light has 3 signals: red, yellow and green. It turns out that the point is in our perception of light.

Red

The first thing that comes to mind when you mention red is danger. However, the main reason why exactly red was chosen to prohibit traffic is for visibility from a greater distance. According to Rayleigh's Law, discovered in 1871, the longer the wavelength, the less light is scattered. Of all the colors available to the human eye (not counting purple), it is red that has the maximum wavelength and is 620-740 nanometers.

Although the Rayleigh scatter was discovered later than the first traffic light, the choice of red for the red signal was based on experience gained on the railroad, as the inventor of the world's first automatic traffic controller John Peak Knight was a railway engineer.

But the first traffic light did not last long: on January 2, 1869, the gas in the lantern exploded, seriously injuring the policeman who was driving it. Because of this incident, traffic lights were banned in Britain and reappeared on the streets of London after 60 years.

Yellow

Garrett Morgan's patent.

According to the same Rayleigh law, yellow belongs to the "silver" in the competition for the best visibility - its wavelength is 570-590 nanometers. Orange is even more visible, which is why in modern traffic lights yellow often has an orange tint.

The first three-color traffic light was patented by Garrett Morgan in 1923, who then sold the patent to General Electric for $ 40,000. Legend has it that he witnessed an accident on a street corner and decided that there was not enough time for drivers to stop before as the red light turns on, therefore, it was necessary to come up with a third, warning signal. So the traffic light got yellow.

By the way, until the 90s of the last century, in some countries, yellow traffic lights were used instead of red. The fact is that in the dark in poorly lit areas, the red light was poorly visible to drivers. However, after the invention of LED traffic lights, red was "revived" and yellow was again used only as a warning signal.

Green

The wavelength of green is 495-570 nanometers, which is less than that of red and green. Therefore, it is seen worse than red and yellow, but better than other primary colors available to our perception.

It is interesting that the prototype of tricolor automobile traffic lights also became railway ones. However, the "trio" of colors was somewhat different. Red indicated a stop signal, green indicated readiness, and white allowed movement. But it was difficult for train drivers to distinguish white from lanterns or stars, which led to numerous accidents. Therefore, it was decided to abandon the white color and the railway traffic light became two-color: red prohibited traffic, and green allowed.

By the way, some traffic lights in Japan use blue instead of green - and this is due to the fact that in the Japanese language for a long time the same hieroglyph was used to denote both green and blue.

But why why why
Was the traffic light green?
And because, because, because,
That he was in love with life.

© Zinoviev N.N.

A traffic light (from Russian light and Greek φορός - "carrier") is an optical device that carries light information. We all know from childhood that traffic signals are red, yellow and green, and sometimes blue and moon-white. Red light prohibits movement, yellow light is usually a warning signal that attracts attention, and green, blue and white signals allow movement. Why are these colors used in traffic lights to control traffic around the world?

In 1868, English inventor John Peak Knight proposed using a device similar to a railway semaphore to regulate traffic in London near the British Parliament. During the day, the signals "stop" and "move with caution" were indicated by arrows that could take different positions, and in the evening, a rotating gas lamp was used for the same purposes, with the help of which, respectively, red and green signals were supplied.

At the beginning of the 20th century, the first electric traffic lights began to be installed in America, first with two signals - red and green, and then a yellow signal was added to them. In the USSR, the first traffic light was installed in 1930, but instead of the usual green signal, then blue was used. In addition, until 1959, when the USSR joined the International Convention on Road Traffic and the Protocol on Road Signs and Signals, the traffic light colors were in reverse order - the top was green and the bottom was red.

Of course, these traffic light colors were not chosen by chance. The choice was influenced by several factors, one of which is the psychology of human perception of various colors. Red is traditionally considered a warning of danger, and green, on the contrary, is the color of life, tranquility.

But one of the main reasons for this choice of colors is the dependence of the degree of light scattering on its wavelength. According to Rayleigh's law, the degree of light scattering is inversely proportional to the fourth power of the wavelength. This means that short-wave radiation - blue and violet - is scattered more strongly. And red, as a color with a longer wavelength, will therefore be visible from a greater distance. Obviously, the most important is the warning of danger and prevention of emergencies, therefore the stop signal is indicated in red. For the same reason (the degree of scattering), the blue signal, as having a shorter wavelength and scattering more strongly, gave way to green.

Surprisingly, in Japan, a green traffic light is called blue. The fact is that when the first street traffic lights appeared in Japan, the signals in them were red, yellow and blue. Over time, the blue lenses of traffic lights were replaced by green ones, but the custom of calling the traffic permitting signal “blue” remained. The peculiarity of the Japanese language is that, therefore, the Japanese call many green objects blue.