Today it is very difficult to imagine traffic rules without the main tool for streamlining traffic, which is a traffic light. It is designed to adjust and facilitate both vehicular and pedestrian traffic. There are different traffic light signals, depending on their functions. 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 require the use of orange traffic lights instead of yellow ones. Signals can be placed 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 various 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 settlements, at the intersection of a road with tram tracks, in front of a bicycle path and a carriageway. They can also be seen where the roadway narrows to allow oncoming traffic to pass alternately.
Interesting fact!The first three-section traffic light was installed in Detroit in 1920.
two-section
Traffic lights with two sections are used to regulate the flow of traffic in the territories of industrial enterprises and organizations, as well as during the narrowing of the roadway to organize a single-lane reverse traffic flow.
Single section traffic light with yellow light
Such a one-color traffic light is found at unregulated intersections and pedestrian crossings.
Traffic lights with additional section
Traffic lights can also 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 the traffic rules, as follows: the contours of the arrows on all signals of a conventional three-color traffic light mean that its action extends only in one specified direction.
An additional section of a traffic light with a green arrow on a black background allows traffic according to the traffic rules, but does not provide advantages during the siding. 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 lights.
Such traffic lights are installed in those places where it is necessary to organize conflict-free traffic at intersections. If one of these traffic lights turns green, then when 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
Reversing traffic lights are used to regulate traffic along the lanes of the carriageway. These are dedicated band 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 in a specific lane. The green arrow, which is directed down, on the contrary, allows movement. The yellow diagonal arrow indicates that the lane mode has been changed and indicates in which direction you need to leave it.
Traffic lights to control traffic across a pedestrian crossing
Typically, such traffic lights have only two types of signals: The first one allows, the second one forbids. As a rule, they correspond to green and red colors. The signals themselves can be of different shapes. Often they are depicted as a stylized silhouette of a person: standing red and walking green. For example, in America, the prohibition signal is made in the form of a red raised palm, meaning "stop." Sometimes 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. Modern traffic lights for convenience are equipped with a digital countdown display. For blind people, sound devices are mounted in traffic lights.
To regulate the movement of trams
A traffic light for a tram, as a rule, is placed in front of areas with limited visibility, long ascents and descents, at a tram depot and in front of arrows. There are two types of traffic lights for the tram: green and red. They are installed either to the right of the tracks, or hung in the center above the contact wire. Basically, such traffic lights notify tram drivers about 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 signals: traffic rules
Round lights mean the following: a static green signal allows the movement of vehicles or pedestrians, and a flashing green traffic light means that a prohibition signal will light up soon, but traffic is still allowed.
Interesting fact!In general, residents of large cities spend about six months of their lives waiting for a traffic signal to pass.
What does a yellow traffic light mean? It warns that the prohibiting signal will be replaced by an enabling one or vice versa, and for the duration of its action prohibits movement. 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 lights burning at the same time indicate that it is forbidden to move further, and the green light will soon turn on. The white-moon signal of the traffic light informs that the alarm is working, and you can continue driving. Such traffic lights are installed on tram and railway tracks.
Traffic lights that 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 allows a U-turn, unless this is prohibited by 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, then 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, a traffic light or a marking?
The rules of the road imply the following priority: the main one is the traffic controller, then the traffic light, then the sign and then the markings. The signals of the traffic controller have priority over traffic signals and traffic signs. They are mandatory. All traffic signals, except for flashing yellow, are more significant than road signs. All road users are obliged to follow the instructions of the traffic controller, even if they contradict traffic lights, signs and markings.
The capital of Germany has a traffic light with thirteen signals. It is not so easy to understand his testimony right away.
Traffic lights are a common thing these days, and you, like all other drivers, are required to follow the rules: stop at a red light, prepare for a yellow one, and pass on a green one.
There is no doubt that traffic lights should be in densely populated cities. Be that as it may, this is the only way to control traffic when there is no police nearby.
Riding every day from home to office, we can’t even imagine a road without at least one traffic light, but there were times when traffic lights didn’t exist at all. Of course, the roads were relatively free...
So, as already mentioned, when you get behind the wheel, you must adhere to certain rules. Traffic lights are the same all over the world and consist of three different colors that have their own specific purpose. But how did it happen that the traffic light is exactly red, yellow and green? Why isn't it purple, brown and grey? There are several suggestions on this topic, but first a little history.
It's no secret that the automotive industry pioneered many important things that are still used throughout the world today, but in turn, it had to borrow something from other industries. A good example is a traffic light.
The first traffic light saw the light in 1868 in London. It was used exclusively to manage rail traffic at the intersection of George and Bridge Streets. The design was quite simple, but performed its function very well. It was made up of two vertical switches that could change to a horizontal position to indicate to trains that they should stop. At a 45-degree angle, the system meant what yellow light does today: attention.
And now the most interesting thing: since the signaling device was completely invisible at night, the engineers decided to install primitive lights on it that would display the "stop" and "attention" modes. What was their color choice? Red for "stop" and green for "attention".
You are probably wondering how the green light became a signal for "attention"? Well, no one knows for sure, but that all changed a few years later when traffic lights made their way into the automotive industry.
A very important moment happened in 1912 in the USA (where else?) thanks to Lester Farnsworth Wire, in charge of traffic in the Salt Lake City Police Department. The first manually operated traffic light had only two colors: red and green. Although at that time there were practically no cars on the roads and the rules of the road had not yet been prescribed, the drivers were surprised by the new invention, so the presence of a policeman was necessary to force them to obey the device.
The first three-color traffic lights appeared again on the railway, but the trio was slightly different: red for "stop", green for "attention", white for "free". While the first two have a more or less obvious meaning, the white signal has become a headache for the authorities. Similar lights, whether they were stars or street lights, misled the drivers, leading to fatal collisions.
Why are traffic lights red, yellow and green
The color red is most often associated with blood and thus was chosen as a prohibitory signal. Symbolizing a dangerous situation leading to serious consequences, red has always been chosen as the color to encourage vehicles to stop and thereby avoid accidents.
As for green, color symbolism also became the reason for its use. As with red, green is the source of human emotion. It is associated with something relaxing (such as nature) that will not have a powerful negative effect on drivers. In addition, the green color is easy to recognize at night.
The choice of yellow was surprising. Many believe that it symbolizes the sun, which is also considered a relaxing and at the same time attention-grabbing element.
Traffic lights have evolved over the years, especially in terms of their effectiveness for colorblind people. Commissioners in many countries have dealt with this issue in different ways, whether it was traffic lights with double red light or sections of different shapes. One way or another, the classic design had to be slightly changed.
Since color blindness is one of the most common forms of visual impairment, these days a little orange is mixed with red - in this case, color blind people are able to notice a brake light. For the same purpose, a shade of blue is added to green.
Why are traffic lights red, yellow and green
Every resident of even the smallest town remembers from childhood the lessons on traffic rules regarding the rules for crossing the road. It is human nature to grow, and many gradually turn from pedestrians into drivers. To properly drive on the road, you need to understand not only road signs and markings, but also traffic lights.
Traffic lights at the intersection
The most famous are three-color traffic lights, consisting of the following set of colors:
- Red traffic light . In a stable burning state, driving on a red traffic light is prohibited from driving on the road on which the traffic light is installed. A flashing red light also prohibits movement, but also notifies you of the imminent switching of signals. . This type of signal is most often used at a railway crossing, and on ordinary roads this goal is achieved by turning on the red and yellow signals at the same time.
- Yellow traffic light . In a stable burning state, it prohibits movement in all cases, except for the situation when the driver crosses the road lane, but does not have time to slow down his vehicle before marking. In this situation, it is necessary, if possible, to leave the intersection area. A yellow flashing traffic light allows traffic, and also notifies of an unregulated intersection and a pedestrian overpass.
- What does a green traffic light mean? . In a stable burning state, it allows movement on the road lane. A green flashing traffic light also allows you to move, but also warns of the expiration of the burning time.
Also on many roads there are possible additions to the traffic light. Recently, it has become common to set timers that indicate the operating time of the enable signal. Additionally, there may be arrows that are mounted at the level of the green light either on one side or on both sides.
What do traffic lights mean
The traffic rules for various traffic signals with arrows can be characterized as follows:
| Traffic light with two arrows | Tram traffic light | Trackless vehicle | ||
| Single lane traffic | two lane traffic | Three lane traffic | ||
| Only central green traffic light | Movement only forward | Movement only forward | Movement only forward | Movement only forward |
| Central green traffic light + right arrow | Move forward + right | Move forward + right | Forward for all, right for rightmost lane only | |
| Central green signal + left arrow | Move forward + left | Move forward + left + turn around | Move forward for everyone, move left or turn around only for the leftmost lane | |
| Central green signal + both arrows | Movement is allowed in all directions | Forward movement + turns + turn around | Moving forward for everyone, turning for the outer lanes according to the rules, turning only for the left lane | |
| Red traffic light + right arrow | Movement only to the right | Movement only to the right | Movement only to the right and only for the right lane. All other lanes are prohibited. | |
| Red traffic light + left arrow | Movement only to the left | Movement only to the left or turn | Movement for the left lane only: turn or U-turn. The rest of the lanes are standing. | |
| Red signal + both arrows | Forward movement is prohibited, turns are allowed | Forward movement is prohibited, turns and U-turns are allowed | Forward movement is prohibited, turns in both directions and a U-turn from the leftmost lane are allowed | Forward movement is prohibited, turns in both directions are allowed only from the extreme lanes, a U-turn is allowed only from the extreme left lane |
| Only red signal | Road up | Road up | Road up | Road up |
For a set of a standard traffic light and one arrow, the requirements are less stringent.
So let's take a three-lane road as an example.. If the green traffic light with an arrow to the right is on, then the rules indicated in the table will apply to the central and right lanes. At the same time, standard traffic rules apply for the left lane. The inhibit signal is subject to the same restrictions. In the daytime, such an addition to the traffic light is clearly visible, but it is not always possible to see it at night. For this reason, black arrow outlines are glued to the central signal, indicating the action for a particular lane of the road. If there is no such schematic representation on the green light itself, the signal is valid for all road users, regardless of their location on the road. There are also traffic lights that have arrows instead of the usual round traffic signal. In this case, traffic control occurs only for those directions indicated by the arrows.
At night, most traffic lights turn off and they enter a flashing yellow mode. In this case, the intersection is considered unregulated and must be passed in accordance with the relevant traffic rules.
Pedestrian traffic light and bicycle crossing signal
At the traffic lights for the specified traffic participants there are only 2 sections. A person is depicted for pedestrians, and their two-wheeled transport is drawn for cyclists.. In the area of pedestrian crossings, traffic lights are increasingly equipped with a timer that indicates the waiting time and the time allotted for the crossing. Additionally, for the deaf, a speaker can be installed that announces the allowed direction of the transition, as well as its beginning and end.
In some cases, if there are bicycle paths, reduced analogues of three-section road traffic lights can be used, under which a white plate with a bicycle sign is fixed.
Reverse traffic signals
These signals are used on roads of the same name, when on some lanes traffic can be carried out both in one direction and in the other direction. The direction of travel along one or another lane of the reverse road is determined by the degree of congestion for each side. The following types of signals are used:
- a red cross in the shape of the letter "X" - prohibits movement on a specific lane of a reverse road;
- yellow arrow pointing to the right - instructs the driver to change lanes located nearby on the right side;
- green arrow straight - allows traffic in this lane.
These types of roads are not widely used in the Russian Federation, so few drivers are familiar with such traffic organization.
The meaning of traffic lights for rail transport
Traffic lights for trams
For trams, a white four-cell traffic light is used, made in the form of a “T” symbol. Movement for them is allowed only when the lower signal is on, and the upper cells indicate possible directions of movement.
The railway traffic light also often has a white lamp in its arsenal, which regulates traffic through the crossing:
Traffic lights at a railroad crossing can also be both red and flash alternately. In this case, the passage is strictly prohibited. Movement is allowed only when both lamps are turned off.
Fine for non-compliance with traffic lights
For violation of the instructions of the electronic traffic controller, the following penalties are prescribed:
- red light fine- not less than 1,000 rubles, upon repeated passage to a prohibiting traffic signal, at least 5,000 rubles or deprivation of a VU for a period of 4-6 months, article 12.12 of the Code of Administrative Offenses of the Russian Federation;
- yellow traffic ticket- for the first violation threatens 1000 rubles, in case of repeated violation the fine will be 5000 rubles or deprivation of a driver's license for a period of 4 to 6 months;
- non-observance of the stop line before the intersection- not less than 800 rubles.
- when entering the reverse lane with the traffic light off- at least 5,000 rubles, because due to the traffic light working on the other side, the movement can be regarded as driving into the oncoming lane;
- in case of non-observance of rebuilding on a reverse road- not less than 500 rubles under Article 12.15 of the Code of Administrative Offenses.
Compliance with traffic lights allows you to regulate traffic in such a way that road users are in safer and more comfortable conditions. Therefore, in order not to increase the likelihood of getting into an accident for yourself and others, you should be careful on the roads. This will help to keep intact not only your budget, but also your life.
Video: What do the traffic lights and the traffic controller and the rules of the intersection mean.
The order of alternation of traffic lights corresponds to the international Convention on Road Signs and Signals. Traffic lights alternate in the following sequence: red - red with yellow - green - yellow - red. Alternation of signals red - green - yellow - red or red - yellow - green - yellow is allowed.
A red solid signal prohibits movement across the entire width of the carriageway. Varieties of the red signal:
A contour black arrow on a red background of a round shape prohibits movement in the direction of the arrow;
An oblique red cross prohibits movement along the lane over which it is installed;
The red silhouette of a man forbids pedestrian traffic;
Red flashing prohibits entry to a railway crossing, bridge, pier, etc.
A yellow solid signal obliges all drivers to stop before the stop line, with the exception of those who could not stop before the intersection.
Yellow connected to red warns that the green signal is on.
A yellow flashing signal warns of the presence of an intersection and does not prohibit movement.
A green steady signal in the absence of any additional sections of the traffic light allows movement along the entire width of the carriageway in all directions.
Varieties of green signal:
A black arrow on a green background of a square, round shape, as well as a green arrow on a black background of a round shape - permission to move in the direction of the arrow;
A green arrow on a black background of a square shape, pointing down, allows movement in the lane over which it is installed;
A signal in the form of a green silhouette of a person allows pedestrian traffic;
The green arrow of the additional section of the traffic light allows movement in the direction of the arrow, regardless of the signal of the main traffic light;
A flashing green signal warns of the end of the enable signal.
Permission for the movement of public transport depends on the combination of the included signals of the upper and lower rows of a special traffic light. Turning on the lower signals movement is prohibited in all directions.
Studies have shown that there is a so-called critical section before the intersection and, being within this section, the driver cannot stop in time in front of the stop line when changing the permissive signal to prohibitive.
The critical section is defined as the distance from the stop lines to the point where 10% of drivers cannot stop. The length of the critical section depends on the speed of movement. So, at a speed of 50 km/h, the length of this section is 43 m and the travel time for this section is 3.1 s; at a speed of 60 km - the length of the section is 58 m and the travel time is 3.5 s; at a speed of 80 km - the length of the section is 91 m and the travel time is 4.1 s.
Hence, the travel time of the critical section at different speeds varies within 3-4 s. This prompted us to use a flashing green signal as a warning and take the flashing time equal to the time of passage of the critical section. In order not to reduce the throughput of the intersection. with a permission signal, a green flashing signal is introduced in part at the expense of the duration of the yellow, which will allow you to safely pass the intersection.
Types of traffic lights. Traffic lights are classified according to their functional purpose - transport and pedestrian; by design - one, two-section, three-section and three-section with additional sections; according to the role performed in the process of motion control - the main ones, backups and repeaters.
The main two groups of traffic lights: transport and pedestrian, which in turn are divided into types. There are 8 types of traffic lights and 2 types of pedestrian ones. The first traffic light number means the group, the second number - the traffic light type.
traffic lights Type 1 have three round signals with a diameter of 200 or 300 mm, arranged vertically or horizontally.
The first type is used with additional sections, in which the direction of movement is indicated by arrows (arrows on a black background). Traffic lights of this type are used to regulate all directions of traffic at intersections. Their use is allowed at railway crossings, intersections with tram and trolleybus lines, in narrowings of the carriageway, etc.
Traffic lights 2 types. On the lenses of the traffic light, the contours of the arrows are applied. indicating permitted or prohibited movement. In this case, the green signal (arrow) is applied on a black background. Type 2 traffic lights are used to regulate traffic in certain directions (indications on the arrow lens).
Traffic lights type 3. They are used as repeaters and in conjunction with type 1 traffic lights.
They are installed under the main traffic light at a height of 1.5-2 m from the roadway. The diameter of the signals is 100 mm. If the main one has an additional section, then the repeater will be equipped with an additional section. Traffic lights of this type can be installed to control cycling.
Traffic lights type 4. They are used to control entrances to separate traffic lanes, with reverse traffic.
They are installed above each lane at its beginning. They have a horizontal arrangement of signals; on the left - in the form of an oblique red cross, on the right - in the form of a green arrow pointing downwards. Both signals are executed on a black rectangular background. Overall dimensions 450 x 500 mm.
These traffic lights can be used together with type 1 traffic lights if the reverse traffic is not organized across the entire width of the carriageway. In this case, the type 1 traffic light does not apply to lanes with reverse traffic. This lane may be delimited by a double broken line 1.9 when the type 4 traffic light is turned off.
Traffic light type 5. Has 4 signals of pale moon color of a round form with a diameter of 100 mm. This traffic light is used in cases of conflict-free regulation of the movement of trams, shuttle buses, trolleybuses moving along a specially allocated lane. In the scheme of organization of traffic at the intersection, a conflict-free passage is provided, i.e., these types together with the general flow, therefore, there is no need to use this type at the intersection.
Traffic light type 6. It has two (or one) round red signals with a diameter of 200 or 300 mm, located horizontally and operating in the alternate flashing mode. When the signals are off, movement is allowed. They are installed in front of railway crossings, drawbridges, berths, ferry crossings, in places where special vehicles enter the road.
Traffic light type 7. It has one yellow signal, constantly working in flashing mode. It is used at unregulated intersections of increased danger.
Type 8 traffic lights. They have two vertical signals of red and green colors of round shape W 200 or W 300 mm. They are used for temporary narrowing of the carriageway, when alternate traffic is organized along one lane. They are also used to control low-intensity traffic in the internal territories of garages, enterprises and organizations where a speed limit has been introduced.
Pedestrians have two vertically arranged signals of a round or square shape with a circle diameter or a square side of 200 mm or 300 mm. All pedestrian crossings at the intersection controlled by traffic lights are equipped.
Traffic lights with a large size are installed on the main streets, squares, on roads with the speed of T.S. 60 km/h
Traffic light design. The traffic light consists of separate sections (Fig. 1) and each section is designed for a specific signal. Depending on the type of traffic light, the sections have different shapes, symbols, light sources, etc. Common to all sections is the presence of an optical device placed in a separate housing.
Figure 15 - Traffic light device
The sections are interconnected by threaded hollow bushings 1, through which the supply wires are passed. The section consists of a body 8, a sun visor 4 and a cover 6. They are made of sheet steel or plastic. An optical device is mounted in the cover, which consists of a reflector 7, a colored diffuser lens 3 and a movable glass 10 with an electric lamp. When the glass is moved, the filament of the lamp is set at the focus of the reflector. To connect the current supply at the bottom of the section there is a block 9.
Light source.
As a light source, incandescent lamps are used, both for general and special purposes. So, gas-light tubes or emitting diodes are used as a light source. The main disadvantage of an incandescent lamp - for general use - is the large length of the filament, which is difficult to focus, low vibration resistance of the lamps, and also have a short service life (500-800 hours):
It has been proven that filament burnout occurs mainly due to inhomogeneity in wire diameter, helix pitch, electrical resistance and evaporation rate.
In some traffic light designs, halogen lamps are used. They have high specific light output and compact filament at small sizes, and these lamps focus well. However, these lamps were not widely used due to their high cost.
Two simultaneously working lamps can be used in one section, but this requires the installation of a special reflector and a bifocal lens. Such a solution is associated with a complication of the design and an increase in cost.
Abroad, a curved gas-light tube has found application as a light source. The tubes contain a filler of red, yellow or green colors, which eliminates the need for a colored lens. For the glow of the tubes, a voltage of over 2000 V is required, so a transformer is required. They have a long service life, but in terms of signal strength they are 5-6 times inferior to modern traffic lights with incandescent lamps.
Traffic light lenses.
In recent years, plastic lenses have become widespread in our country and abroad. They have advantages over glass ones in ease of manufacture, higher strength under impact and vibration loads, as well as less weight (about 3 times). These lenses are usually made from polycarbonate.
Diffuser lenses are designed to redistribute the light flux into space. To do this, a patterned, rhombic, prismatic or drop-shaped pattern is formed on their inner side. For modern lenses, this angle is in the range of 5-15°, which ensures normal visibility of the signal on multi-lane roads (100 m).
Reflector.
The reflector is characterized by two main internal surfaces: paraboloid, which provides the concentration of the light flux, and conical (or cylindrical), designed to increase the depth of the reflector and thereby reduce the burnout of the lens dye.
With a short focal length, there is a danger of a false traffic signal (phantom effect), when the beam from an extraneous light source, hitting the reflector, returns to the observer again.
In the designs of modern reflectors, the focal plane AA is brought as close as possible to the plane of the light hole, behind which the non-working conical surface begins.
As a rule, the condition is met:
(13)
where: is the diameter of the light aperture of the reflector, mm.
Reflectors are made of steel, aluminum alloys or plastics with subsequent processing of the inner surface. Plastic reflectors with a working surface obtained by vacuum deposition are widely used.
Anti-phantom devices.
An anti-phantom device in a traffic light is a sun visor, but at a low position of the sun (for example, east-west, west-east), all traffic lights may glow.
There are several methods to eliminate the phantom effect, but they require a change in the design of the reflector or traffic light lens.
The reflector with the so-called anti-phantom cross consists of mutually perpendicular segmented plates with slots for the location of a halogen lamp (Fig. 1).
A beam of light falling from an external light source onto the reflector is deflected and absorbed by the surface of the plates. Another solution is carried out by installing a special anti-phantom lens in front of the light filter 1, consisting of two parts 2, 3, each of which has a sawtooth profile (Fig. 2). A ray of the sun, falling on an inclined surface, is thrown onto a horizontal blackened step and absorbed by it.
Rice. 16 - Anti-Phantom Cross
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Fig. 17 - Lens that absorbs the sun's rays
Best of all - related to the long-wavelength part of the visible spectrum, that is, red and orange. Even in foggy weather, they are visible at a considerable distance. This is especially important for the prohibition signal.
Yellow light travels worse than red, but better than green. It is most suitable for warning signal.
And the permissive signal of the traffic light can be green, because it is not so necessary to see it from afar.
Who Invented the Traffic Light
The first street traffic light appeared in London in 1868. It was invented by the English engineer Knight. The prototype, apparently, was a railway traffic light, which by that time had long been used to regulate rail traffic. Before the traffic lights were put into operation, detailed rules were published in the newspapers of London, from which people first learned what green meant and what red meant. Installed in front of the English Parliament building, the first traffic light was mechanical: the color signals changed in it using a system of drive belts. For this, he served nearby - a special policeman was on duty.
Soon, the device was equipped with a gas lantern so that the color changes were visible even at night. However, this innovation turned out to be fatal for the fate of the first street traffic light. The lantern once exploded and mortally wounded a nearby policeman. Since then, the history of the traffic light has been interrupted for almost half a century.
The new birth of the automatic traffic controller took place in 1914 in Cleveland, USA, and a little later in Chicago and New York. The traffic lights were electric this time, but just like the London one, they had only two signals - red and green. Yellow color appeared only in 1918.
In Russia, the first traffic light was installed in 1924 in Moscow at the intersection of Kuznetsky Most and Petrovka streets. With the development of technology, automatic control was gradually introduced. So, in 1955, the first “green wave” appeared in the capital on the Garden Ring, consisting of five traffic lights: a car that got green at the first traffic light passed all the others without hindrance.
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Traffic light colors in order
The red color is very clearly visible in any weather: when the sun is shining brightly, it is raining, or there is fog. From a physical point of view, red has the maximum wavelength. Perhaps that is why it was chosen as forbidden. All over the world, the meaning of red is the same.
Traffic light green
The other traffic signal is green. This is the color of calmness, peace. It has a relaxing effect on the human brain. The traffic light is green for traffic. You can see it far enough, any driver sees this color long before the traffic light passes and calmly, without braking, overcomes the intersection.
However, as they say, there is an unwritten rule according to which it is still worth slowing down when driving through a dangerous intersection, even when the traffic light is green. This action often helps to avoid serious accidents.
Yellow - pay attention
The yellow color of the traffic light is intermediate. It has a warning function and encourages road users to pay attention. It is said that yellow symbolizes the mind, intuition and ingenuity. It usually lights up after red, urging drivers to prepare for movement. As practice shows, many drivers perceive the yellow signal of a traffic light as permissive and start moving. This is wrong, although it is not punishable by penalties. When the yellow color lights up, you need to squeeze the clutch, get ready, but to start moving, it’s better to wait for the green one, especially since it’s only a couple of seconds to wait.
In reverse order: green, yellow, red - the traffic light is not working. In modern devices, after the green, the red color immediately lights up, while in the last minutes the green starts flashing.
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You can also sometimes see a continuously flashing yellow traffic light. This indicates that the traffic light is disabled or broken. Most often, traffic lights flash yellow at night.
Pedestrian traffic light
There is also a traffic light to regulate pedestrian traffic. What colors does it use? Red and green - definitely, but yellow is missing as unnecessary. A person does not need special preparation for crossing the road.
Walking little men are usually depicted at pedestrian traffic lights. For the convenience of pedestrians, a time counter has recently been used. A special stopwatch counts how many seconds are left before the opposite signal is turned on.
As in conventional traffic lights, red indicates traffic is prohibited, while green indicates that the passage is open.
When passing through an intersection, drivers should be aware that pedestrians are taking advantage. So, for example, at an intersection, a car turns right at a green traffic light, while pedestrians crossing a perpendicular road also turn green. In this case, the motorist must give way to all pedestrians and only then continue driving.
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What is a "green wave"
In large metropolitan areas, traffic on highways is accompanied by a large number of traffic lights that regulate traffic. The traffic light, the colors of which are known to everyone, switches them at a certain frequency. This frequency is automatically adjusted and ensures the safety of vehicles.
"Green wave" is tied to the speed of the car. It is assumed that, moving at a certain average speed, the driver, hitting the green traffic light, will also get green along the entire length of the highway. The three colors of the traffic lights switch at regular intervals, and there is consistency between a number of traffic lights. At all intersections of the route, coordinated according to this principle, there is the same cyclicity.
The "Green Wave" was developed for the convenience of crossing intersections; technically, this is not particularly difficult to implement. As a rule, signs are additionally installed on such highways with the recommended speed, which will ensure non-stop passage of intersections.
An assistant to the driver and pedestrian is a three-eyed traffic light. The colors switch in order and adjust the ride, ensuring the safety of all road users. By following the rules of crossing intersections in good faith, you can avoid serious accidents and unpleasant situations on the roads.
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What color are traffic lights?
But why, why, why
Was the traffic light green?
And that's why, that's why, that's why
That he was in love with life.
A traffic light (from Russian light and Greek φορός - “bearing”) is an optical device that carries light information. We all know from childhood that traffic lights are red, yellow and green, and sometimes blue and moon-white. Red light prohibits movement, yellow 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 regulate traffic around the world?
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In 1868, the English inventor John Peak Knight proposed using a device similar to a railway semaphore to control traffic in London near the British Parliament. During the day, the “stop” and “move with caution” signals were indicated by arrows that could take different positions, and in the evening, a rotating gas lamp was used for the same purpose, with the help of which red and green signals were given, respectively.
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 then blue was used instead of the usual green signal. In addition, until 1959, when the USSR joined the International Convention on Road Traffic and the Protocol on Road Signs and Signals, the colors of the traffic lights were in reverse order - the top was green and the bottom red.
Of course, these colors of traffic lights were not chosen by chance. The choice was influenced by several factors, one of which is the psychology of human perception of different colors. Red is traditionally considered a warning of danger, while green, on the contrary, is the color of life and tranquility.
But one of the main reasons for this choice of colors is the dependence of the degree of scattering of light 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 scatter the least in the atmosphere, therefore, it will be visible from a greater distance. Obviously, the most important is the warning of danger and the prevention of accidents, so 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 lights appeared in Japan, the signals in them were red, yellow and blue. The blue lenses of traffic lights were eventually replaced with green ones, but the custom of calling the traffic signal “blue” remained. The peculiarity of the Japanese language is that green is considered a shade of blue, so the Japanese call many green objects blue.
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Traffic light colors
Why did red, yellow and green become the colors of traffic lights around the world? Why didn't you choose any other colors? In fact, there are two reasons that explain this choice.
Explanation number one is related to physics, the second reason is directly related to psychology and the possibilities of human perception of colors.
According to experts, red is the main danger signal for many animals. For road users, red also signals a dangerous situation on the road - the possibility of running over a pedestrian or getting into an accident in case of disobedience to this traffic light signal. Red, falling into the field of view, should excite the nerve centers of both drivers and pedestrians and become for them a symbol of a nearby danger.
It is also worth mentioning that it is this spectrum of colors - red, yellow and green - that is always perfectly perceived by the human eye. This is due to physical factors, in particular the wavelength.
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A person should easily perceive red and green signals, identifying them as allowing and forbidding, this is how it happens.
By the way, even a color-blind person, who is not able to distinguish between red and green, is able to identify them by different shades of gray.
It should also be mentioned that our eyes react differently to light of different wavelengths, reacting with different sensitivity - more or less. The choice of green as a permissive signal is also not accidental. Green is as close as possible to the level of the most perceived part of the spectrum. That is, a person is able to see the green color from the greatest distance.
Types of traffic lights, the meaning of traffic signals
Today it is very difficult to imagine traffic rules without the main tool for streamlining traffic, which is a traffic light. It is designed to adjust and facilitate both vehicular and pedestrian traffic. There are different traffic light signals, depending on their functions. 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.
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Types of traffic lights
The most common are three-color traffic lights with round signals: red, yellow and green. Traffic rules in some countries require the use of orange traffic lights instead of yellow ones. Signals can be placed 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 various 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 settlements, at the intersection of a road with tram tracks, in front of a bicycle path and a carriageway. They can also be seen where the roadway narrows to allow oncoming traffic to pass alternately.
two-section
Traffic lights with two sections are used to regulate the flow of traffic in the territories of industrial enterprises and organizations, as well as during the narrowing of the roadway to organize a single-lane reverse traffic flow.
Single section traffic light with yellow light
Such a one-color traffic light is found at unregulated intersections and pedestrian crossings.
Traffic lights with additional section
Traffic lights can also 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 the traffic rules, as follows: the contours of the arrows on all signals of a conventional three-color traffic light mean that its action extends only in one indicated direction.
An additional section of a traffic light with a green arrow on a black background allows traffic according to the traffic rules, but does not provide advantages during the siding. 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 lights.
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Traffic lights to regulate traffic in certain directions
Such traffic lights are installed in those places where it is necessary to organize conflict-free traffic at intersections. If one of these traffic lights turns green, then when 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
Reversing traffic lights are used to regulate traffic along the lanes of the carriageway. These are dedicated band 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 in a specific lane. The green arrow, which is directed down, on the contrary, allows movement. The yellow diagonal arrow indicates that the lane mode has been changed and indicates in which direction you need to leave it.
Traffic lights to control traffic across a pedestrian crossing
Typically, such traffic lights have only two types of signals: The first one allows, the second one forbids. As a rule, they correspond to green and red colors. The signals themselves can be of different shapes. Often they are depicted as a stylized silhouette of a person: standing red and walking green. For example, in America, the prohibition signal is made in the form of a red raised palm, meaning "stop." Sometimes 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. Modern traffic lights for convenience are equipped with a digital countdown display. For blind people, sound devices are mounted in traffic lights.
To regulate the movement of trams
A traffic light for a tram, as a rule, is placed in front of areas with limited visibility, long ascents and descents, at a tram depot and in front of arrows. There are two types of traffic lights for the tram: green and red. They are installed either to the right of the tracks, or hung in the center above the contact wire. Basically, such traffic lights notify tram drivers about 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.
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Traffic signals: traffic rules
Round lights mean the following: a static green signal allows the movement of vehicles or pedestrians, and a flashing green traffic light means that a prohibition signal will light up soon, but traffic is still allowed.
What does a yellow traffic light mean? It warns that the prohibiting signal will be replaced by an enabling one or vice versa, and for the duration of its action prohibits movement. 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 lights burning at the same time indicate that it is forbidden to move further, and the green light will soon turn on. The white-moon signal of the traffic light informs that the alarm is working, and you can continue driving. Such traffic lights are installed on tram and railway tracks.
Traffic signals that 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 allows a U-turn, unless this is prohibited by the corresponding traffic sign next in priority.
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The green arrow of the additional section has a similar meaning. If this signal is turned off, or the red outline is on, then 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, a traffic light or a marking?
The rules of the road imply the following priority: the main one is the traffic controller, then the traffic light, then the sign and then the markings. The signals of the traffic controller have priority over traffic signals and traffic signs. They are mandatory. All traffic signals, except for flashing yellow, are more significant than road signs. All road users are obliged to follow the instructions of the traffic controller, even if they contradict traffic lights, signs and markings.
The capital of Germany has a traffic light with thirteen signals. It is not so easy to understand his testimony right away.
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Topic 6.1. Traffic lights.
Classic three-section transport traffic light.
Any of us knows from childhood that a red traffic light prohibits movement, and now both drivers are required to stop at the stop line.
But not everyone knows how a modern “advanced” traffic light works, what signals it can have and how exactly they alternate.
At the exam in the traffic police you will be asked:
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What does the combination of red and yellow traffic lights mean?
The answer should not leave you in doubt - a short combination of red and yellow signals informs drivers that the green signal will turn on soon.
Red and yellow went out, green turned on, and you can move in all directions (unless, of course, otherwise indicated by signs or markings).
But do not rush to start moving. How many troubles and tragedies the author of these lines saw when the neighbors on the road blindly oriented towards the green signal. And this is not just advice, this is a requirement of the Rules.
Rules. Section 13. Clause 13.8. When the permissive signal of the traffic light is turned on, the driver is obliged to give way to vehicles completing the movement through the intersection, and to pedestrians who have not completed the crossing of the carriageway of this direction.
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That is, before you start moving, you need to make sure that those who have now turned red have stopped. Someone may simply not have time to stop, and someone is in such a hurry that he is ready to slip through the intersection risking his life (it would be fine if only his own, but also someone else's).
Well, finally, the drivers on the intersecting road stopped at their stop lines, and now you can start moving. We are still green.
Green burned out, burned out and blinked.
And again, at the exam in the traffic police, someone will definitely get this question:
What does a flashing green traffic light mean?
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And again, the answer is obvious - a flashing green signal informs drivers that its time is running out and yellow will soon turn on.
Is it possible to move on the green flashing? Do not doubt it is possible. Its duration is expiring, but it hasn't expired yet!
Another thing is that the green will blink for a short time - it will blink only three times, and then it will go out.
The green will go out, but then the yellow will light up. And here is what is said about the lone yellow signal in the Rules, in clause 6.2:
"The yellow signal prohibits movement and warns of the upcoming change of signals."
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And here it is important for the driver to understand! - If the lone yellow is on, then the next one will be red! That means you have to stop!
Now imagine that the yellow turned on when there were 5-10 meters left to the stop line. At a speed of 60 km / h, you can only keep the car by applying emergency braking! And even then, you will have to stop already at the intersection (having crossed the stop line and risking getting hit from behind). Novice drivers often do this (slow down sharply on yellow), and if an aggressive “experienced driver” was driving behind, then a blow from behind to a beginner in this situation is guaranteed.
Meanwhile, the Rules prohibit sudden braking anywhere and everywhere (except when it is necessary to prevent an accident):
Rules. Section 10. Clause 10.5. The driver must not brake hard unless it is necessary to prevent an accident.
That is, if now the driver of the brown car brakes sharply, he will violate the requirement of paragraph 10.5 of the Rules. And in the event of an accident, both will be to blame - the driver of the red car is to blame because he did not keep a safe distance, and the driver of the brown car - because he braked unnecessarily sharply.
The Rules treated this situation with understanding and allowed movement to the yellow traffic light (if it is no longer possible to stop smoothly in front of the stop line):
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Rules. Section 6. Clause 6.14. Drivers who, when the yellow signal is turned on, cannot stop without resorting to emergency braking, are allowed to continue further movement.
And they may also ask you about this at the exam: “Are you allowed to continue driving if, when the yellow traffic light turns on after the green one, you can stop in front of the intersection only by applying emergency braking?”
And here the answer should be absolutely clear to you - it is allowed. Simply allowed, in any direction you want.
A lone yellow will not burn for long - in just a couple of seconds it will change to red, and the cycle will start over. But already on a red signal, drivers should definitely stop at the stop line.
Turning on the green signal opens the movement in all directions. But at the same time, no one canceled the general principle of safety:
- you can directly from all lanes;
- to the right - from the right lane;
- to the left and to turn - from the left lane.
2. Only straight ahead or right.
2. Only go straight, left or reverse.
But now the signs are given special instructions. And we remember that signs (or markings) that allow a left turn also allow a U-turn.
But the U-turn must always be carried out only from the leftmost lane!
In what directions can the driver of the brown car continue to move?
1. Only straight or left.
2. Straight, left or reverse.
In what directions can the driver of the red car continue to move?
2. To the left or in the opposite direction.
And it's not all about traffic lights. If the traffic is not intense, then it is irrational to keep drivers at the stop lines, and the traffic light can be switched to the so-called yellow flashing signal mode.
That is, red and green do not turn on at all, and only yellow is turned on all the time. Moreover, it does not just burn, but it flashes at a frequency of once per second. This is how the Rules say about this signal:
Rules. Section 6. Clause 6.2. A yellow flashing signal allows traffic and informs about the presence of an unregulated intersection or pedestrian crossing.
In this situation, drivers must independently determine the order of passage, guided by the general principle of “interference on the right”.
In the traffic police collection there is a problem (shown below), solving which you are often mistaken. Some of you choose the third answer for some reason. Most likely, because they inattentively read the question. And the question says "with a yellow flashing traffic light"! And, consequently, this intersection has become unregulated. And, therefore, it is necessary to be guided by the signs of priority.
You intend to continue straight ahead. What do you do when the yellow traffic light flashes?
1. Give way only to the tram.
2. Give way only to the car.
3. Wait for the green traffic light to turn on and continue driving.