Passes from the moment of activation brake system until it comes to a complete stop. The length of the brake directly depends on the movement of the vehicle, the way, and also the road conditions. For example, at a speed of 50 km/h, the average stopping distance will be approximately 15 m, and at 100 km/h it will be 60 m.
Please note that braking distances vehicle depends on many factors, such as: speed, vehicle weight, road surface, weather conditions, braking method, as well as the condition of the vehicle's wheels and its braking system.
Determine the braking distance of the car using the following formula: S = Ke x V x V / (254 x Fc), where
S is the stopping distance of the car in ,
Ke - braking coefficient, which is equal to 1 y,
V is the vehicle speed (in km/h) at the start of braking,
Fc - coefficient of adhesion to the road (different indicators depending on weather conditions),
0.7 - dry asphalt,
0.4 - wet road,
0.2 - packed snow,
0.1 - icy road.
Please note that there are several various ways braking, namely: smooth, sharp, stepped and intermittent. Smooth braking apply in a calm environment. Perform a gradual increase in pressure on the brake pedal, and this will ensure a smooth decrease in vehicle speed. It is with this method of braking that you will get the longest braking distance.
remember, that hard braking When you press the brake pedal hard, it usually causes the wheels to lock up, which can lead to loss of control and the car skidding. If you choose step braking, then press the pedal several times, but do each subsequent press with great effort, and so on until the car comes to a complete stop. When intermittent braking, press the pedal hard, almost until the wheels lock, and then release the pedal. Follow the same principle until the car comes to a complete stop.
Instruction
The braking distance of the car is directly dependent on several factors. These include: the speed of the car, its weight, the chosen method of braking, the surface of the road, the presence of water or ice on it. If you are moving at a speed of 100 kilometers per hour, then the length of the braking distance can be 55-60 meters. It is clear that bad brakes or "bald tires" can increase the stopping distance.
To accurately calculate the stopping distance, you can use the following formula: S = Ke x V x V / (254 x Fc). The symbols in it mean the following: S - braking distance, calculated in meters; Ke - braking coefficient (for passenger cars mobiles, it is equated to one); V - speed (km / h) with which the car was moving when braking began; Фc - coefficient indicating the grip of the car's wheels with pavement. Here, under different weather conditions, the values \u200b\u200bcan change, and are: 0.7 - dry asphalt road; 0.4 - wet asphalt road; 0.2 - road covered with rolled snow; 0.1 - road covered with a layer of ice. It can be seen that the highest coefficient is when driving along dry road, i.e. in optimal driving conditions.
Regardless of who is driving the car - experienced driver with twenty years of experience or a beginner who only yesterday received his long-awaited rights - an emergency can occur on the road at any time due to:
- traffic violations by any participant traffic;
- faulty condition of the vehicle;
- sudden appearance on the road of a person or animal;
- objective factors ( bad road, poor visibility, falling stones, trees, etc. on the road).
Safe distance between cars
According to clause 13.1 of the Rules of the Road, the driver must keep a sufficient distance from the vehicle in front, which will allow him to slow down in time.
Failure to keep a distance is one of the main causes of transport accidents.
In the event of a sudden stop in front of the vehicle in front, the driver of the car following him closely does not have time to brake. The result is a collision of two, and sometimes more vehicles.
To determine the safe distance between cars while driving, it is recommended to take an integer numerical value of the speed. For example, the speed of a car is 60 km/h. This means that the distance between him and the vehicle in front should be equal to 60 meters.
Possible consequences of collisions
According to the results of technical tests, a strong impact of a moving car on any obstacle corresponds in strength to a fall:
- at 35 km / h - from a 5-meter height;
- at 55 km / h - 12 meters (from 3-4 floors);
- at 90 km / h - 30 meters (from the 9th floor);
- at 125 km / h - 62 meters.
It is clear that a collision of a vehicle with another vehicle or other obstacle, even if not high speed threatens people with injury, and in the worst case, death.
Therefore, when it occurs emergencies every effort must be made to avoid such collisions and avoid the obstruction or emergency braking.
What is the difference between stopping distance and stopping distance?
Stopping distance - the distance that the car will travel for the period from the moment the driver detects obstacles to the final cessation of movement.
It includes:
What does braking distance depend on?
A number of factors affecting its length:
- braking system response speed;
- the speed of the vehicle at the moment of braking;
- type of road (asphalt, unpaved, gravel, etc.);
- condition of the road surface (after rain, sleet, etc.);
- tire condition (new or with worn tread);
- tire pressure.
Braking distances passenger car is directly proportional to the square of its speed. That is, with an increase in speed by 2 times (from 30 to 60 kilometers per hour), the length of the braking distance increases by 4 times, by 3 times (90 km / h) - by 9 times.
emergency braking
Emergency (emergency) braking is used when there is a danger of a collision or collision.
You should not press the brake too sharply and strongly - in this case, the wheels are blocked, the car loses control, it begins to slide along the track "skid".
Symptoms of locked wheels during braking:
- the appearance of vibration of the wheels;
- reduction of vehicle braking;
- the appearance of a scraping or screeching sound from tires;
- the car has a skid, it does not respond to steering movements.
IMPORTANT: If possible, it is necessary to make a warning braking (half a second) for cars following behind, release the brake pedal for a moment and immediately begin emergency braking.
Types of emergency braking
1. Intermittent braking - apply the brake (without allowing the wheels to lock) and release completely. Repeat this until the car comes to a complete stop.
At the moment the brake pedal is released, the direction of travel must be aligned to avoid skidding.
Intermittent braking is also used when driving on slippery or rough roads, braking in front of potholes or icy areas.
2. Step braking - apply the brake until one of the wheels locks, then immediately release the pressure on the pedal. Repeat this until the car stops moving completely.
At the moment of easing the pressure on the brake pedal, it is necessary to align the steering wheel with the direction of movement in order to avoid skidding.
3. Engine braking on vehicles with mechanical box gears - press the clutch, change to a lower gear, again to the clutch, etc., alternately lowering to the lowest.
IN special occasions You can downshift not in order, but several at once.
4. Braking with ABS: if the car has automatic box gears, during emergency braking, it is necessary to press the brake with maximum force until it comes to a complete stop, and on machines with a manual gearbox, they simultaneously press hard on the brake and clutch pedals.
When the ABS system is activated, the brake pedal will twitch and there will be a crackling sound. This is normal, you must continue to press the pedal with all your might until the car stops.
PROHIBITED: During emergency braking, use parking brake- this will lead to a turn of the car and an uncontrolled skid due to complete blocking car wheels.
It may happen that the integrity of the car body and the safety of its passengers will depend on the length of the braking distance. A car at speed simply cannot freeze abruptly after pressing the brake, even if it has high-quality tires and efficient system braking. After the brake pedal is pressed, the car in any case overcomes a certain distance, and this distance is called the braking distance.
The driver must constantly calculate the length of the braking distance in accordance with one of the rules for traffic safety, which says that the braking distance must be less than the distance to the obstacle.
In this situation, it all depends on the reaction and skill of the driver, the sooner he presses the brake and correctly calculates the length of the braking distance, the sooner, and more successful than a car slow down.
Braking distance of the car at a speed of 60 km / h
Deformation of the body in a collision at a speed of 60 km / h
Length stopping way also depends not only on the driver, but also on other related factors: on the quality of the road, speed, weather conditions, the state of the brake system, the design of the brake system, car tires, and many others.
note that the weight of the car does not affect the stopping distance. This is due to the fact that the weight of the car increases the inertia of the car when braking, while preventing braking, but increases the grip of the tires due to the increased mass of the car.
These physical properties compensate each other, while practically not affecting the length of the braking distance.
The speed of braking directly depends on the method of braking. sharp brake to the stop, will cause the machine to skid or skid (if the machine is not equipped with an ABS system).
Gradual pressing on the pedal applied when on the road good visibility and calm environment, it is not suitable for emergency situations. When pressed intermittently you can lose control, but then stop quickly. Also possible stepped pressing(similar in effect to ABS system).
There are special formulas that allow you to determine the length of the braking distance. We will try to calculate the formula for different conditions, depending on the type of road surface.
Formula for determining the stopping distance
Braking distance on dry pavement
We remember the lessons of physics, where ? is the coefficient of friction, g is the free fall acceleration, and v is the speed of the vehicle in meters per second.
The situation is as follows: the driver is driving car Lada whose speed is 60 km/h. Literally 70 meters away is an elderly woman who, forgetting about safety rules, hastily catches up with fixed-route taxi(standard situation for Russia).
Let's use this very formula: 60 km/h = 16.7 m/sec. Dry asphalt has a friction coefficient of 0.7, g - 9.8 m/s. In fact, depending on the composition of the asphalt, it is from 0.5 to 0.8, but still take the average value.
The result obtained by the formula is 20.25 meters. Naturally, this value is only relevant for ideal conditions when the machine is equipped with quality rubber And brake pads, the braking system is in good condition, when braking you do not go into a skid and do not lose control, from many other idealized factors that are not found in nature.
Also, to double-check the result, there is one more braking distance formula:
S = Ke * V * V / (254 * Fs), where Ke is the braking coefficient, for passenger cars it is equal to one; Фс - coefficient of adhesion with a coating of 0.7 (for asphalt).
Substitute the speed of the vehicle in km/h.
It turns out that the braking distance is 20 meters for a speed of 60 km / h, (for ideal conditions), if the braking is sharp and without skidding.
Braking distance on the surface: snow, ice, wet asphalt
BMW cars on trial
The friction coefficient helps to indicate the length of the stopping distance under different road conditions. Odds for different road surfaces:
- Dry asphalt - 0.7
- Wet asphalt – 0,4
- Rolled snow - 0.2
Let's try to substitute these values into the formulas, and find the values of the braking distance for the road surface in different time year and under different weather conditions:
- Wet asphalt - 35.4 meters
- Rolled snow - 70.8 meters
- Ice - 141.6 meters
It turns out that on ice the length of the braking distance is practically seven times higher relative to dry asphalt (as well as the substituted factor). The braking distance is affected by the quality winter tires, physical properties.
Testing has shown that with the ABS system, the stopping distance is significantly reduced, but still, on ice and snow, ABS does not affect, but rather worsens braking performance when compared with a braking system without ABS. However, in ABS, to a large extent, everything depends on the settings and the presence of a brake force distribution system (EBD).
The advantage of ABS in winter time - full control over the control of the car, which minimizes the occurrence of uncontrolled skidding when braking. Principle ABS work similar to step braking on non-ABS vehicles.
The ABS system reduces the stopping distance by: dry and wet asphalt, rolled gravel, road marking.
On ice and packed snow, the use of ABS increases the braking distance by 15 - 30 meters, but allows you to maintain control over the car, without taking the car into a skid. This fact should be taken into account.
How to brake on a motorcycle?
Correctly braking on a motorcycle is a rather difficult task. Can be braked rear wheel, front, or two, skid or engine. At improper braking on high speeds you can lose your balance. In order to calculate the braking distance of a motorcycle at 60 km / h, the data is also substituted into the formula. Considering at the same time a different braking coefficient and coefficient of friction.
Braking distance of motorcycles
- Dry asphalt: 23 - 33 meters
- Wet asphalt: 35 - 46 meters
- Mud and snow: 70 - 95 meters
- Ice: 95 - 128 meters
The second indicator is the braking distance when the motorcycle is skidding.
Any vehicle owner should know and be able to calculate the length of the braking distance, and it is better to do this visually.
It should be remembered that in the event of a traffic accident along the length of the skid, which will remain on the road surface, you can determine the speed of the vehicle before colliding with an obstacle, which may indicate an excess allowable speed driver and make him the culprit of the accident.
It is not in vain that the signs have a recommended speed for vehicles of 60 km / h, because by adhering to this figure, the driver can make a safe movement and stop in time. This is especially true in the event of an unforeseen situation where you need to apply emergency braking or a sharp maneuver. If you still need to slow down, then the stopping distance, in this case, will be about 25 meters, but many aspects affect the figure, such as: car weight, tire quality, serviceability and much more. Let's look into this in more detail.
If the road surface, namely asphalt, is dry, then braking will be minimal, because the road holding is excellent. Wet asphalt will increase stopping distances due to the water's ability to reduce friction. If we consider another road, for example, where the ground is on the surface, then the path also increases, the same can be said about concrete, because of its smoothness. In numbers, this is not 25, but already 125 meters, again at 60 kilometers per hour.
ABS application
This system is deciphered as Anti-Lock, and it is used to reduce the braking distance. How does it work? It turns out that when the driver depresses the brake pedal to the maximum, the system prevents the wheels from completely blocking. Otherwise, sliding occurs, and there will be no talk of controllability.
In any case, you need to monitor the health of the brake system, because it may not even help.
Weight of car and tires
It will be very difficult for a car to cope with a large mass, so you should never forget about keeping your distance. It is best if the driver prepares for the trip in advance and knows what braking distance his car has. No less important role is played by the tread pattern, the presence of spikes, seasonality, etc., in general, so that the tires meet many requirements. This is especially true and at the same time dangerous when the tire has already worn out and worn out, and the road is wet. In this case, the braking distance will be very long and may lead to an accident.
What is the braking distance for a car and a motorcycle at a speed of 60 km/h?
Any motorist knows that often we are separated from an accident in just a fraction of a second. A car moving at a certain speed cannot freeze in place, as if rooted to the spot, after pressing the brake pedal, even if you have Continental tires, which traditionally rank high in the ratings, and brake pads with a high brake pressure ratio.
After pressing the brake, the car still overcomes a certain distance, which is called the brake or stopping way. So stopping distance is the distance traveled vehicle from the moment the brake system is applied to a complete stop. The driver must at least approximately be able to calculate the stopping distance, otherwise one of the basic rules of safe movement will not be observed:
- the stopping distance must be less than the distance to the obstacle.
Well, here such an ability as the driver’s reaction speed comes into play - the sooner he notices an obstacle and presses the pedal, the earlier car will stop.
The length of the braking distance depends on such factors:
- movement speed;
- quality and type of road surface - wet or dry asphalt, ice, snow;
- the condition of the tires and braking system of the vehicle.
Please note that such a parameter as the weight of the car does not affect the length of the braking distance.
The braking method is also of great importance:
- sharp pressing to the stop leads to uncontrolled skidding;
- gradual increase in pressure - used in a calm environment and with good visibility, in emergency situations does not apply;
- intermittent pressing - the driver presses the pedal several times to the stop, the car may lose control, but stops quickly enough;
- step pressing - works on the same principle ABS system. the driver completely locks and releases the wheels without losing contact with the pedal.
There are several formulas that determine the length of the stopping distance, and we will apply them for different conditions.
The braking distance is determined by a simple formula:
From the course of physics, we remember that μ is the coefficient of friction, g is the acceleration of free fall, and v is the speed of the car in meters per second.
Imagine the situation: we are driving a VAZ-2101 at a speed of 60 km / h. At 60-70 meters we see a pensioner who, forgetting about any safety rules, rushed across the road after a minibus.
We substitute the data in the formula:
- 60 km/h = 16.7 m/s;
- the coefficient of friction for dry asphalt and rubber is 0.5-0.8 (usually 0.7 is taken);
- g = 9.8 m/s.
We get the result - 20.25 meters.
It is clear that such a value can only be for ideal conditions: good quality tires and brakes everything is fine, you braked with one sharp press and all the wheels, while not going into a skid and not losing control.
You can double-check the result using another formula:
S \u003d Ke * V * V / (254 * Fc) (Ke is the braking coefficient, for passenger cars it is equal to one; Fs is the coefficient of adhesion with the coating - 0.7 for asphalt).
IN this formula put the speed in kilometers per hour.
We get:
- (1*60*60)/(254*0.7) = 20.25 meters.
Thus, the length of the braking distance on dry asphalt for passenger cars moving at a speed of 60 km / h, under ideal conditions, is at least 20 meters. And that's with hard braking.
Wet asphalt, ice, rolled snow
Knowing the coefficients of adhesion to the road surface, you can easily determine the length of the braking distance under various conditions.
- 0.7 - dry asphalt;
- 0.4 - wet asphalt;
- 0.2 - packed snow;
- 0.1 - ice.
Substituting these data into the formulas, we obtain the following values for the length of the stopping distance when braking at 60 km/h:
- 35.4 meters on wet pavement;
- 70.8 - on packed snow;
- 141.6 - on ice.
That is, on ice, the length of the braking distance increases by 7 times. By the way, on our website Vodi.su there are articles on how to properly drive a car and brake in winter. Also, safety during this period depends on right choice winter tires.
If you are not a fan of formulas, then on the net you can find simple calculators stopping distance, whose algorithms are based on these formulas.
Stopping distance with ABS
home ABS task- do not let the car go into an uncontrolled skid. The principle of operation of this system is similar to the principle of stepped braking - the wheels are not completely blocked and thus the driver retains the ability to drive the car.
Numerous tests show that with ABS brake shorter way to:
- dry asphalt;
- wet asphalt;
- rolled gravel;
- on the plastic sheet.
On snow, ice, or muddy soil and clay, braking performance with ABS is somewhat reduced. But at the same time, the driver manages to maintain control. It is also worth noting that the length of the braking distance largely depends on the settings of the ABS and the presence of EBD (brake force distribution system).
In short, the fact that you have ABS does not give you an advantage in the winter. The length of the braking distance can be 15-30 meters longer, but then you do not lose control of the car and it does not deviate from its route. And on the ice, this fact means a lot.
Motorcycle stopping distance
Learning how to properly brake or slow down on a motorcycle is not an easy task. You can brake front, rear or both wheels at the same time, engine braking or skidding is also used. If you slow down incorrectly at high speed, you can very easily lose balance.
The braking distance for a motorcycle is also calculated using the above formulas and is for 60 km / h:
- dry asphalt - 23-32 meters;
- wet - 35-47;
- snow, mud - 70-94;
- black ice - 94-128 meters.
The second digit is the skid braking distance.
Any driver or motorcyclist should know the approximate stopping distance of their vehicle when different speeds. When registering an accident, traffic police officers can determine the speed at which the car was moving along the length of the skid.
