Braking distance from 60. How to calculate the braking distance

What is the stopping distance for a car and a motorcycle at 60 km / h?

Any motorist knows that often a split second separates us from an accident. A car moving at a certain speed cannot stop rooted to the spot after pressing the brake pedal, even if you have Continental tires, which traditionally occupy high places in the ratings, and brake pads with a high brake pressure ratio.

After pressing the brake, the car still covers a certain distance, which is called the braking or stopping distance. Thus, the braking distance is the distance that the vehicle travels from the moment it was triggered. brake system to a complete stop. The driver must be at least approximately able to calculate the stopping distance, otherwise one of the basic rules will not be observed safe movement:

the stopping distance must be less than the distance to the obstacle.

Well, here such an ability comes into play as the driver's reaction speed - the sooner he notices an obstacle and presses the pedal, the earlier car will stop.

The stopping distance depends on the following factors:

movement speed;
quality and appearance road surface - wet or dry asphalt, ice, snow;
condition of tires and brake system of the car.

Please note that parameters such as vehicle weight do not affect the braking distance.

The method of braking is also of great importance:

sharp pressing all the way to the stop leads to an uncontrollable skid;
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 all the way, the car may lose control, but stops quickly enough;
step pressing - the ABS system works according to the same principle. the driver completely locks and releases the wheels without losing contact with the pedal.

There are several formulas that determine the stopping distance, and we will apply them for different conditions.

The braking distance is determined using a simple formula:

From the physics course, we remember that μ is the coefficient of friction, g is the acceleration of gravity, 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 for a minibus.

We substitute the data into the formula:

60 km / h \u003d 16.7 m / s;
the coefficient of friction for dry asphalt and rubber is 0.5-0.8 (usually 0.7 is taken);
g \u003d 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 hard pressing and with all wheels, while not skidding and not losing control.

You can double-check the result using one more formula:

S \u003d Ke * V * V / (254 * Fs) (Ke - braking coefficient, for passenger cars it equals one; Фс - coefficient of adhesion to the surface - 0.7 for asphalt).

The speed is substituted into this formula in kilometers per hour.

We get:

(1 * 60 * 60) / (254 * 0.7) \u003d 20.25 meters.

Thus, the braking distance on dry asphalt for passenger cars moving at a speed of 60 km / h is at least 20 meters under ideal conditions. And this is subject to sharp braking.

Wet asphalt, ice, rolled snow

Knowing the traction coefficients, it is easy to determine the braking distance under various conditions.

0.7 - dry asphalt;
0.4 - wet asphalt;
0.2 - rolled snow;
0.1 - ice.

Substituting these data into the formulas, we obtain the following stopping distance lengths when braking at 60 km / h:

35.4 meters on wet asphalt;
70.8 - on packed snow;
141.6 - on ice.

That is, on ice, the braking distance increases by 7 times. By the way, on our website Vodi.su there are articles on how to properly drive and brake in winter time... Also, safety during this period depends on the right choice winter tires.

If you are not a fan of formulas, then on the net you can find simple stopping distance calculators, the algorithms of which are based on these formulas.

Stopping distance with ABS

The main task of ABS is to prevent the car from going into an uncontrolled skid. The principle of operation of this system is similar to the principle of step braking - the wheels are not completely blocked, and thus the driver remains able to drive the car.

Numerous tests show that with ABS brake the path is shorter by:

dry asphalt;
wet asphalt;
rolled gravel;
on plastic markings.

On snow, ice or on soggy soil and clay, braking performance with ABS is slightly reduced. But at the same time, the driver manages to maintain control. It is also worth noting that the braking distance largely depends on the ABS settings and the presence of EBD - brake force distribution system).

In short, the fact that you have ABS does not give you a winter advantage. The braking distance can be 15-30 meters longer, but on the other hand, 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 braking distance

Learning how to brake or brake properly on a motorcycle is not an easy task. You can brake with the front, rear or both wheels at the same time, engine or skid braking is also used. If you brake incorrectly on high speed, it is very easy to lose your 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;
ice cover - 94-128 meters.

The second number is the skid braking distance.

Any driver or motorcyclist should know the approximate stopping distance of his vehicle at different speeds. Traffic police officers, when registering an accident along the length of the skid, can determine the speed with which the car was moving.

Any motorist knows that often a split second separates us from an accident. A car moving at a certain speed cannot freeze in place, rooted to the spot after pressing the brake pedal, even if you have Continental tires, which traditionally occupy high places in the ratings, and brake pads with high brake pressure coefficient.

After pressing the brake, the car still covers a certain distance, which is called the braking or stopping distance. Thus, braking distance is the distance that a vehicle travels from the moment the braking 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 comes into play as the speed of the driver's reaction - the earlier he notices the obstacle and presses the pedal, the earlier the car will stop.

The stopping distance depends on the following factors:

movement speed;
the quality and type of road surface - wet or dry asphalt, ice, snow;
condition of tires and brake system of the car.

Please note that parameters such as vehicle weight do not affect the braking distance.

The method of braking is also of great importance:

sharp pressing all the way to the stop leads to an uncontrollable skid;
gradual increase in pressure - it is used in a calm environment and with good visibility, in emergency situations it is not used;
intermittent pressing - the driver presses the pedal several times all the way, the car may lose control, but stops quickly enough;
step pressing - the ABS system works according to the same principle, the driver completely locks and releases the wheels without losing contact with the pedal.

ABS application

This system stands for Anti-lock braking system, and it is used to reduce the braking distance. How does it work? It turns out that when the driver squeezes the brake pedal as much as possible, the system prevents the wheels from locking completely. Otherwise, slipping 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.

Machine weight and tires

It will be very difficult for a car to cope with large massso you should never forget about keeping your distance. It is best if the driver prepares for the trip in advance and knows what kind of braking distance his car has. An equally important role is played by the tread pattern, the presence of studs, seasonality, etc., in general, so that the tires meet many requirements. This is especially true and at the same time dangerous when the tire is already worn out and worn out, and the road is wet. In this case, the braking distance will be very long and can lead to an accident.

Braking distance of the car.

1. Braking distance avcar - Rdistance traveled by the vehicle from start to end of braking.

The normative values \u200b\u200bof the braking distance of vehicles under certain conditions are given in the section tbrake control requirements GOST R 51709-2001 " Motor vehicles... Safety requirements for technical condition and verification methods ”.

Braking Performance Standards vehicle when checking in road conditions.

The standard values \u200b\u200bof the braking distance are established at:

a) initial braking speed during road tests - 40 km / h;

b) not exceeding the technically permissible maximum mass of the vehicle;

c) when braking at an initial speed of 40 km / h, a traffic corridor with a width of no more than 3 meters is observed (the vehicle should not leave this corridor with any of its parts).

d) driving on a straight flat horizontal dry clean road with cement or asphalt concrete pavement (coefficient of adhesion of tires to the road 0.7 - 0.8);

e) braking with the service brake system in the emergency full braking mode by a single action on the control.

According to GOST R 52051-2003 “Power-driven vehicles and trailers. Classification and definitions ", categories are designated:

M1. Vehicles used for the carriage of passengers and having, in addition to the driver's seat, no more than eight seats (passenger cars).

M2. Vehicles used for the carriage of passengers, which, in addition to the driver's seat, have more than eight seats, the maximum mass of which does not exceed 5 tons (buses).

M3. Vehicles used for the carriage of passengers, which, in addition to the driver's seat, have more than eight seats, the maximum mass of which exceeds 5 tons (buses.

N1. Vehicles intended for the carriage of goods, having maximum mass no more than 3.5 tons

N2. Vehicles intended for the carriage of goods having a maximum mass exceeding 3.5 tonnes but not exceeding 12 tonnes.

N3. Vehicles intended for the carriage of goods having a maximum mass exceeding 12 tonnes.

2. The braking distance of the vehicle at the initial braking speed is higher40 km per hour.

GOST R 51709-2001 “Motor vehicles. Safety Requirements for the Technical Condition and Test Methods "provides a method for recalculating the braking distance standards depending on the initial braking speed of the vehicle, i.e. speed exceeding 40 km per hour.

To do this, the GOST provides the following formula:

St = AVo +Vabout 2/26Jmouth., Where

Vо is the initial braking speed of the vehicle, km / h;

Just - steady-state deceleration, m / s 2;

A - coefficient characterizing the response time of the brake system.

When recalculating the braking distance standards S t, the values \u200b\u200bof the coefficient A and the steady-state deceleration J set for various categories of vehicles should be used, given in the table below (according to GOST R 51709-2001):

PBX name	ATC category (tractor unit as part of a road train)	Initial data for calculating the standard stopping distance S T of the vehicle in running order
PBX name	ATC category (tractor unit as part of a road train)	AND	J mouth, m / s 2
Passenger and utility vehicles	M 1	0,10	5,2
Passenger and utility vehicles	M 2, M 3	0,15	4,5
Cars with trailers	M 1	0,10	5,2
Trucks	N 1, N 2, N 3	0,15	4,5
Trucks with a trailer (semi-trailer)	N 1, N 2, N 3	0,18	4,5

For cars:

- with an initial braking speed of 50 km / h, the braking distance will be 23 meters;

- with an initial braking speed of 70 km / h, the braking distance will be 43 meters;

- with an initial braking speed of 90 km / h, the braking distance is 69 meters;

- at 110 km / h - the braking distance is 100 meters;

- at 130 km / h - 138 meters;

- at 150 km / h the braking distance will be 181 meters.

For buses at an initial braking speed of 50 km / h, the braking distance is 29 meters, at 70 km / h - 52 meters, at 90 km / h - 83 meters.

For trucks without a trailer - similar to buses.

For trucks with a trailer (semi-trailer):

- with an initial braking speed of 50 km / h, the braking distance will be 30 meters;

- with an initial braking speed of 70 km / h, the braking distance will be 55 meters;

- with an initial braking speed of 80 km / h, the braking distance will be 69 meters;

- with an initial braking speed of 90 km / h, the braking distance will be 85 meters;

The braking distance values \u200b\u200bare recalculated for driving conditions on dry clean asphalt in braking modes according to the operating rules specific brands vehicles with and without ABS.

3. The stopping distance of a vehicle is the main component of the stopping distance.Stopping distance is the distance that a car travels from the moment the driver detects a danger on the road to a complete stop. The stopping distance will be greater than the braking distance by an amount in meters during the driver's reaction time and during the brake system response time.

The driver's reaction time is from 0.4 to 1.2 s and depends on the professionalism of the driver and his physical and psycho-emotional state (the reaction time increases with fatigue, illness, sharply increases with alcohol or drug intoxication).

The response time of the brake system is the time from the moment the brake pedal is depressed until the actuation braking device... Depends on the quality and condition of the braking system, usually up to 0.4 seconds for brakes with hydraulic drive and up to 0.8 seconds for pneumatic brakes.

For reference. 60 km per hour equals 16.7 meters per second (60,000 m: 3600 sec).

4. The braking distance of the vehicle, in addition to the initial braking speed, depends on many other additional factors. This is the condition of the brakes, the condition of the tires, the presence of ABS, the type of road surface, weather conditions. Generalizing indicator of the condition of tires and road conditions is the coefficient of adhesion of the tires to the road.

According to GOST R 51709-2001, the coefficient of adhesion of the wheel to the supporting surface is the ratio of the resulting longitudinal and transverse reaction forces of the supporting surface, acting in contact between the wheel and the supporting surface, to the value of the normal reaction of the supporting surface to the wheel.

According to a short car handbook (NIIAT, 1983), the values \u200b\u200bof the coefficient of adhesion at a speed of 40 km per hour are as follows:

Cover type	Traction coefficient
Cover type	Dry surface	Wet surface
Asphalt concrete, cement concrete pavement	0,7-0,8	0,35-0,45
Macadam	0,6-0,7	0,3-0,4
Dirt road	0,5-0,6	0,2-0,4
The road covered with rolled snow	0,2-0,3	0,2-0,3
Icy road	0,1-0,2	0,1-0,2

Measurement of the actual coefficient of adhesion of tires to the road is carried out in accordance with GOST 33078-2014 “Automobile roads for general use. Methods for measuring the adhesion of a coated car wheel.

No matter who is driving the car - experienced driver with twenty years of experience or a beginner who just yesterday received his long-awaited license - an emergency situation can occur on the road at any time due to:

traffic violations by any participant road traffic;
faulty condition of the vehicle;
the sudden appearance of a person or animal on the road;
objective factors (bad road, poor visibility, falling stones, trees, etc.) on the road.

Safe distance between vehicles

According to clause 13.1 of the Road Traffic Regulations, the driver must keep from the vehicle in front at a sufficient distance that will allow him to brake in time.

Failure to maintain distance is one of the main causes of traffic accidents.

In case of a sudden stop of the vehicle in front, the driver of the car closely following him has no time to brake. The result is a collision of two or 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 60 meters.

Possible consequences of collisions

According to the results of technical tests, a strong impact of a moving car against an obstacle in force corresponds 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 car or other obstacle, even at low speed, threatens people with injury, and in the worst case, death.

Therefore, when emergency situations every effort must be made to avoid such collisions and to avoid obstacles or emergency braking.

What is the difference between the braking distance and the stopping distance?

Stopping distance - the distance that the car will travel during the period from the moment the driver detects obstacles to the final stop of movement.

It includes:

What determines the braking distance

Several factors affect its length:

the speed of the braking system;
vehicle speed at the moment of braking;
type of road (asphalt, dirt, gravel, etc.);
the condition of the road surface (after rain, ice, etc.);
condition of tires (new or with worn out tread);
tire pressure.

The braking distance of a passenger car is directly proportional to the square of its speed. That is, when the speed increases 2 times (from 30 to 60 kilometers per hour), the braking distance increases 4 times, 3 times (90 km / h) - 9 times.

Emergency braking

Emergency (emergency) braking is used when there is a danger of collision or collision.

Do not press the brake too sharply and hard - in this case, the wheels are blocked, the car loses control, it starts to slide along the track "skidding".

Symptoms of locked wheels during braking:

the appearance of wheel vibration;
reducing vehicle braking;
the appearance of a scraping or squealing sound from tires;
the car has skidded, it does not react to steering movements.

IMPORTANT: If possible, it is necessary to make a warning braking (half a second) for cars following behind, momentarily release the brake pedal and immediately start emergency braking.

Types of emergency braking

1. Intermittent braking - apply the brake (without blocking the wheels) and release completely. So repeat until the machine comes to a complete stop.

At the moment of releasing the brake pedal, the direction of travel must be aligned to avoid skidding.

Intermittent braking is also used when driving on slippery or uneven roads, braking in front of pits or icy areas.

2. Step braking - press the brake until one of the wheels locks, then immediately release the pressure on the pedal. Repeat this until the machine stops moving completely.

At the moment of weakening the pressure on the brake pedal, it is necessary to align the direction of movement with the steering wheel 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 cases, you can downshift not in order, but several at once.

4. Braking with ABS: if a car It has automatic transmission gears, during emergency braking, it is necessary to press the brake with maximum force until it comes to a full stop, and on machines with a manual transmission, simultaneously apply strong pressure on the brake and clutch pedals.

When triggered aBS systems the brake pedal will twitch and a crisp sound will be produced. This is normal and you need to keep pressing the pedal with all your strength until the vehicle comes to a stop.

FORBIDDEN: During emergency braking enjoy parking brake - this will lead to a U-turn of the car and an uncontrolled skid due to the complete blocking of the wheels of the car.