Have you already paid attention to warning road signs with a black triangle symbolizing a descent or ascent, and a percentage indicating the steepness of this descent (or ascent)? And, perhaps, they asked themselves the question - but, for example, 12% is how much? And why not indicate the steepness of the slope in degrees?
These signs indicate the tangent of the angle of inclination, expressed as a percentage.
Well, your smile has faded, as if, having unwrapped a package with a gift, you found in it a weighty volume of Dostoevsky. But in a few minutes you will easily operate with the concept of "tangent", and at the same time "sine" and "cosine", surprised that before today they made you tense.
So, lean the ski pole at an angle against the wall in front of a bright lamp. You will see two shadows - one on the wall, the other on the floor. The teachers, to annoy you, called these shadows projections. Accordingly, on the vertical and horizontal planes. The shadow on the wall is called "sine", the one on the floor is called "cosine".
The closer to the wall you move the bottom of the stick, the shorter the “cosine” will be. On the contrary, moving the bottom of the stick away from the wall, you will see that the "sine" is getting smaller, and the "cosine" is getting larger. The ratio of sine to cosine is called tangent.
If you set the stick at a 45 degree angle from the floor, the sine and cosine will be exactly the same. In this case, the tangent will be 1. Or, as your teachers said, the tangent of 45 degrees is 1.
If we look at the side of the road where it has a slope, we will see that the angle of this slope is within 8 degrees from the horizon. The height of the lift, or "sine", is much less than the length of the projection of the road on a horizontal plane - "cosine". Dividing the height of the lift by the length of the horizontal projection, we find that the tangent of the angle of such a slope does not exceed 0.12.
It is convenient to express it as a percentage - for example, 12%. In this case, the tangent of the 45 degree angle is 100%.
Now you can safely use this information. So, after driving 1 kilometer on a road with a slope of 12%, you will rise (or descend) 120 meters. (At such small slope angles, the length of the horizontal projection of the road can be considered equal to the length roads).
Out of curiosity, you can convert the slope angle back to degrees using the calculator on your cell phone, setting it to "scientific" mode, for example: TAN -1 (0.12)=7 degrees. In some calculators: ATAN (0,12)=7.
However, for motorists, this is not the main thing. I hope you have already read my article on the friction coefficient.
So, it turns out the tangent of the angle of inclination is equal to the friction coefficient.
For example, a car parked on a dry asphalt slope with a friction coefficient of 0.7 will begin to slide down if the slope angle is 70% (This is a slope of about 35 degrees, you are unlikely to ever see such a slope.)
But, besides the roads, there are streets of old cities, especially coastal ones, with inclination angles that significantly exceed all kinds of standards. So, when driving in wet weather down an asphalt slope with a steepness of 20%, the braking efficiency drops by half.
And very often you have to move on wet ice with a friction coefficient of 0.1 or less. And this means that you should carefully follow the warning road signs with a black triangle and numbers inside. They are set when the slope angle approaches 10%. If you disregard these signs and stop on the ascent, you will best case- You won't be able to move. And if you slow down on the descent ...
But I am convinced that now nothing like this will happen to you. And I sincerely hope that today I helped you a little, dear mothers - our most responsible and beloved part of humanity.
A road with a steep slope is a danger to safe driving. The driver needs to control the speed, namely to reduce and keep the distance to the nearest car.
The situation can be aggravated during rain and ice. If the driver does not ignore the instructions of road signs, he may end up in a ditch or run into other participants traffic.
A hard braking can lead to an uncontrolled skid, after which the driver may be on oncoming lane.
In this article:
Road sign requirement 1.13
Sign 1.13 steep descent makes it clear to the driver that the car may behave differently on the descent, namely, roll spontaneously.
Therefore, the driver must be vigilant, control speed mode, because on the descent braking distances will be increased.
On any slope, the car may roll if the driver does not use parking brake or transmission of a checkpoint for parking the car.
It will be relevant to use engine braking when passing a steep descent, this will reduce the effort on brake discs and wear process.
Please note that if there is a malfunction brake system the situation on a steep descent can be disastrous. Therefore, you need to choose the lowest possible gear and low speed, or if it is possible to bypass this section of the road.
It’s not worth risking in ice at all if you are not confident in road grip winter tires and the performance of the brake system, since it will not be possible to stop the car on a steep descent.
Rules for installing a sign 1.13
Sign " Steep descent» has its own installation features.
in the city or rural settlement the location of sign 1.13 will be at a distance of 50-100 meters before the start of the descent, and outside the city at a distance of 150-300 meters. If a different distance is used, it must be indicated on plate 8.1.1.
In accordance with the provisions of GOST, the sign is installed if there is the following characteristics roads:
- if present insufficient visibility a car in front, which may unexpectedly be in front when approaching a downhill;
- the length of the road section on which the downward deviation percentage is measured is taken into account;
- and of course, the ability of a standing vehicle to roll down spontaneously.
Depending on the slope angle, sign 1.13 contains information on the slope percentage. Accordingly, the higher the slope, the less speed need to choose the driver for safe driving.
If the descents and ascents are periodic, for example, in mountainous areas, then it is allowed to install a road sign immediately before they begin.
Liability for violation of the sign 1.13
As such, there is no penalty for violating sign 1.13. However, the descent is difficult area roads, for drivers of both directions. Accordingly, if there is a detour ahead of the descent, the driver moving in the oncoming lane has an advantage in the passage.
For violation of the preferential passage by another driver, the offender may be fined 500 rubles, or a written warning under Part 3 of Art. 12.14 Administrative Code of the Russian Federation.
Also on the downhill section due to driver inattention or poor visibility road markings, the driver may be in the oncoming lane.
In this case, liability arises in the form of a fine of 1000-1500 rubles under Part 3 of Art. 12.16 of the Code of Administrative Offenses of the Russian Federation or 5,000 rubles, or deprivation of rights for 4-6 months under Part 4 of Art. 12.16 of the Code of Administrative Offenses of the Russian Federation.
Sign 1.13 "Steep descent"
On road sign 1.13 shows the slope of the road in the form of a black triangle, above which the angle of inclination is indicated as a percentage. Immediately it is worth clarifying that the unit of measurement for angles is degrees, not percentages! So what are the percentages indicated on road signs for a steep descent and a steep ascent? A slope of 45 degrees should be considered as 100%, and the tangent of 45 degrees is 1. If the road slope is 7 degrees, then the tangent of 7 degrees is 0.12, which is why 12% is written on the sign. The second question is why complicate things so much? It turns out that the tangent of the angle of inclination is equal to the coefficient of adhesion with pavement. For example, the coefficient of adhesion of the wheels of a car with wet ice is less than 0.1. If you see 10% downhill, then you must understand that no driving experience, no studded tires and even a headwind will not help you slow down on such a descent! Even if you park the car on such a descent on dry pavement, after which water will flow down the descent, and then it will start to freeze, the car can roll down such a descent!
If you think this is absurd, then watch a lot of videos of cars rolling down on ice...
First of all, when you see this road sign, the driver should slow down and prepare for the descent.
It is worth understanding and remembering:
1) From weather conditions changing grip.
2) Grip with wet ice is less than 0.1, which means that descents and ascents with signs on which more than 10% can be extremely dangerous and insurmountable.
3) On long descents, the most effective braking is engine braking! The steeper the slope, the lower the gear should be.
4) When descending, drivers on the rise (on the opposite lane) have an advantage and you must give way to him, if he enters your lane! According to paragraph 11.7 of the rules in case of difficult passing on the descent, you must give way vehicles, next on the rise.
When signs for a steep descent or a steep ascent indicate a small percentage, many consider it superfluous. This is wrong! It often happens that in conditions of poor visibility (night, fog, snowfall ...) the driver simply does not notice small but long descents or ascents.
Sign 1.13 is set
In the locality: at a distance of 50-100 meters before the start of the descent.
outside locality: at a distance of 150-300 meters before the start of the descent.
Outside the village given sign can be installed together with signs:
8.1.1 - "Distance to the object".
Specifies the distance from the sign to the start dangerous area, V this case down a steep descent.
8.2.1 - "Scope".
Indicates the length of the dangerous section of the road, in this case a steep start.
1.14 - "Steep Climb"
If, after a steep descent, a steep ascent immediately begins, then the sign 1.14 is set directly at the beginning of the ascent.
Have you already paid attention to the warning road signs indicating the steepness of the descent or ascent, and you may have asked yourself the question - and, for example, 12% is how much? And why not indicate the steepness of the slope in degrees?
On signs 1.13 (Steep descent) and 1.14 ( Steep climb) denotes the tangent of the slope, expressed as a percentage. To understand clearly what it is, let's recall the geometry. So, lean your ski pole at an angle against the wall in front of a bright lamp. You will see two shadows - one on the wall, the other on the floor. These are projections, respectively, on the vertical and horizontal planes. The shadow on the wall is called "sine", the one on the floor is called "cosine". The closer to the wall you move the bottom of the stick, the shorter the "cosine" will be. On the contrary, moving the bottom of the stick away from the wall, you will see that the "sine" is getting smaller, and the "cosine" is getting larger. The ratio of sine to cosine is called tangent. If you set the stick at a 45 degree angle from the floor, the sine and cosine will be exactly the same. In this case, the tangent will be 1. Or, as your teachers said, the tangent of 45 degrees is 1. If we look at the side of the road, in the place where it has a slope, we will see that the angle of this slope is within 8 degrees from horizon. The height of the rise, or "sine", is much less than the length of the projection of the road on a horizontal plane - "cosine". Dividing the height of the lift by the length of the horizontal projection, we find that the tangent of the angle of such a slope does not exceed 0.12. It is convenient to express it as a percentage - for example, 12%. In this case, the tangent of an angle of 45 degrees is equal to 100%.
Now you can safely use this information. So, after driving 1 kilometer on a road with a gradient of 12%, you will ascend (or descend) 120 meters.(At such small slope angles, the length of the horizontal projection of the road can be considered equal to the length of the road).
Out of curiosity, you can convert the slope angle back to degrees using the calculator on your cell phone, setting it to "scientific" mode, for example: TAN-1(0,12)=7 degrees. In some calculators: ATAN(0,12)=7. However, for motorists, this is not the main thing.
The ratio of two forces - the force required to move the car with locked wheels, and the force of gravity pressing the car to the road is called adhesion coefficient. So we can easily get the friction coefficients for dry asphalt - 7000/10000 = 0.7, for dirty road– 3000/10000 = 0.3, and for ice – 1000/10000 = 0.1. These values are approximately the same even if the machine is pulled sideways. Why do you need to know this?! Insufficient attention to the friction coefficient or its incorrect assessment is the main cause of accidents on the roads, especially in spring and autumn, when up to 70% of accidents occur because of this.
Turns out, the tangent of the angle of inclination is equal to the friction coefficient. For example, a car parked on a dry paved slope with a friction coefficient of 0.7 will begin to slide down if the tangent of the slope is 70% (This is a slope of about 35 degrees, it is unlikely that you will ever see such a slope.) But, apart from roads, there are streets of old cities, especially coastal ones, with slope angles that significantly exceed all kinds of standards.
So, when driving in wet weather down an asphalt slope with a steepness of 20%, the braking efficiency drops by half. And very often you will have to drive on wet ice with a friction coefficient of 0.1 or less. And this means that you must carefully follow the warning road signs 1.13 and 1.14. They are set when the slope angle approaches 10%. If you ignore these signs and stop on the rise, then at best you will not be able to move. And if you slow down on the descent, the car can skid. Try to brake with the engine on long descents.
It's no secret what the descents and ascents are like. This is especially true for residents of regions where there are mountains. The road here turns into an exciting (but dangerous) adventure, and 1.13 and 1.14 do not get tired of replacing each other.
An important point concerning these signs is the way they are installed: according to the rules, these signs can be installed right at the start ascent or descent. That is, the classic distance of 150-300 meters to the dangerous area may not be here, if the descents and ascents follow each other.
Why percentage? What do the numbers on the sign mean?
Many drivers pay attention to the fact that the steepness of the descent or ascent on these warning signs is indicated as a percentage, and not in the usual "degrees".The fact is that in general - this information is more accurate than the well-known "degrees" to us. Descents are not always perfectly smooth, and their steepness can vary. Set every 50 meters new sign With new information- no way out. Therefore, one sign is installed on which (for example) 20% is written
These figures mean that for every 100 meters of distance traveled, there are 20 meters of descent. After driving 1 kilometer at this angle, you will go down 200 meters! Everything is simple!
Who has the advantage?
In a normal situation, in case of difficult oncoming traffic, the participant on whose side the obstacle is located must give way. On narrow sections of the road, signs and may also appear, which will determine the procedure for passing in this situation.But on the descents and ascents, the participant who goes down (on the descent) is obliged to give way, regardless of which side the obstacle is on. Important! - This rule"works" only when there are warning signs "steep descent" and "steep ascent"
