- What is the braking distance of a car?
- What is the stopping distance formula?
- How to calculate the total stopping time and the total stopping distance?
- What factors influence braking and braking distance?
- What is the braking distance at speeds of 50, 80 and 110 km / h.
- What determines the average braking distance of any car
Imagine how fewer accidents would happen if cars could stop instantly. Unfortunately, the elementary laws of physics say that this is impossible.
It is customary for car manufacturers to “brag” about another indicator: acceleration to 100 km / h. Of course, this is also important. But it would be nice to know how many meters the braking distance will stretch. Indeed, it differs for different cars.
In this article we will talk about what you need to know about the braking distance for each driver in order to protect themselves on the road. Fasten your seat belt and let's go!
What is the braking distance of a car?
The braking distance is the distance that the vehicle will travel after activating the brake system to a complete stop. This is just a technical parameter, which, in combination with other factors, determines the safety of the car. This parameter does not include the response rate of the driver.
The totality of the reaction of a motorist to an emergency and the distance from the start of braking (the driver pressed the pedal) to the complete stop of the vehicle is called the stopping distance.
The rules of the road indicate critical parameters at which the operation of the vehicle is prohibited. The maximum limits are:
|Type of transport:||Braking distance, m|
|Motorcycle / Moped||7,5|
|Bus / truck weighing up to 12 tons||18,3|
|Truck weighing over 12 tons||19,5|
Since the braking distance depends directly on the vehicle speed, the above mentioned distance traveled by the vehicle with a decrease in speed from 30 km / h is considered a critical indicator. (for motor vehicles) and 40 km / h. (for passenger cars and buses) to zero.
Too slow reaction of the brake system always leads to damage to the vehicle and often to injuries of those who are in it. For clarity, a car moving at a speed of 35 km / h will collide with an obstacle with a force identical to a shock when falling from a five-meter height. If the speed of a car in a collision with an obstacle reaches 55 km / h, then the impact force will be identical when falling from the third floor (90 km / h - falling from the 9th floor, or from a height of 30 meters).
These research results show how important it is for the motorist to monitor the condition of the brake system of the car, as well as tire wear.
What is the stopping distance formula?
There are special formulas that help the driver to calculate the length of the braking distance during emergency and normal braking. Of course, they are averaged.
So, normal braking involves soft pressing the brake pedal, for example at a traffic light. In this case, we are guided by the formula:
(Speed in km / h: 10) * (speed in km / h: 10) = stopping distance in meters
That is, if you move at a speed of 50 km / h, the braking distance will be approximately 25 meters. We consider this: 50/10 * 50/10 = 5 * 5 = 25.
With emergency braking, the resulting value is divided into two more. The formula is as follows.
(Speed, in km / h: 10) * (Speed, in km / h: 10) / 2
Count on a specific example. Suppose you are again moving at a speed of 50 km / h and a situation has occurred in which you need to brake urgently. We consider the braking distance as follows: 50/10 * 50/10 / 2 = 5 * 5/2 = 12,5 meters.
You can say that in an emergency there is no time to count and you need to act. Yes, you are absolutely right. But there is one “but.” Each driver moves around the city at about the same speed. Therefore, you can pre-learn the desired value and build on it when needed. Such a simple life hack may one day save someone's life. Therefore, take note of it.
How to calculate the total stopping time and the total stopping distance?
As we noted above, the driver needs time to make a decision on braking. That is, to react. Plus, it takes time to move the foot from the gas pedal to the brake pedal and the machine itself to respond to this action.
There is a formula that averages out the reaction path of the driver. Here she is:
(Speed in km / h: 10) * 3 = reaction path in meters
Imagine the same situation. You drive at a speed of 50 km / h and decided to brake smoothly. While you make a decision, the car will drive 50/10 * 3 = 15 meters. The second value (the length of the real braking distance) we considered higher - 25 meters. As a result, 15 + 25 = 40. This is the distance that your car will cover until you completely stop.
What factors influence braking and braking distance?
We already wrote above that many factors influence the length of the braking distance. We offer to consider them in more detail.
This is a key factor. This refers not only to the speed of the car, but also the reaction speed of the driver. It is believed that the reaction of all is approximately the same, but this is not entirely true. The driving experience, the state of human health, the use of medications, etc., play a role. Also, many "reckless" neglect the law and are distracted by smartphones while driving, which, in the end, can lead to disastrous consequences.
Remember one more important point. If the speed of the car doubles, the length of its braking distance grows 4 times! Here the 1: 1 ratio does not work.
Undoubtedly, the condition of the road surface affects the length of the brake line. On an icy or wet track, it can grow at times. But these are far from all factors. You should also be wary of fallen leaves on which the tires glide perfectly, cracks in the coating, pits and so on.
The quality and condition of the rubber greatly affects the length of the brake line. Often, more expensive tires provide better grip on the car. Please note that if the tread depth has erased more than the permissible value, then the rubber loses its ability to divert enough water when driving on wet roads. As a result, you may encounter such an unpleasant thing as aquaplaning - when the car loses traction and becomes completely uncontrollable.
To reduce the braking distance, it is recommended to maintain optimum pressure in the tires. Which one - the automaker will answer this question for you. If the value deviates up or down, the braking line will increase.
Depending on the coefficient of adhesion of tires with road surface, this indicator will be different. Here is a comparative table of the dependence of the stopping distance on the quality of the road surface (a passenger car whose tires have an average coefficient of adhesion):
|60km / h||80 km / h.||90 km / h.|
|Dry asphalt, m.||20,2||35,9||45,5|
|Wet asphalt, m.||35,4||62,9||79,7|
|Snowy road, m.||70,8||125,9||159,4|
Of course, these indicators are relative, but they clearly illustrate how important it is to monitor the condition of automobile rubber.
Technical condition of the machine
A car can drive on the road only in good condition - this is an axiom that does not require evidence. To do this, conduct routine diagnostics of your car, timely repair and change the brake fluid.
Remember that worn brake discs can double the braking line.
Distraction on the road
While the car is moving, the driver has no right to be distracted from driving the vehicle and controlling the traffic situation. Not only its safety, but the lives and health of passengers, as well as other participants in the movement, depend on this.
Here's what happens in the driver’s brain when an emergency occurs:
- traffic assessment;
- decision making - to slow down or maneuver;
- response to the situation.
Depending on the driver’s innate abilities, the average reaction speed is between 0,8 and 1,0 seconds. This option relates to an emergency, rather than an almost automatic process when slowing down on a familiar stretch of road.
To many, this time period seems insignificant to pay attention to, but ignoring the danger can lead to fatal consequences. Here is a table showing the reaction of the driver and the path traveled by the car:
|Vehicle speed, km / h.||Distance to the moment of pressing the brake (time remains the same - 1 sec.), M.|
As you can see, even a seemingly insignificant second of delay can lead to sad consequences. That is why every motorist should never break the rule: “Do not be distracted and adhere to the speed limit!”
Various factors can distract the driver from control:
- mobile phone - even just to see who is calling (when talking on the phone, the driver’s reaction is identical to the reaction of a person in a state of mild intoxication);
- looking at a passing car or enjoying beautiful scenery;
- fastening seat belt;
- eating while driving;
- crash of a loose DVR or mobile phone;
- clarification of the relationship of the driver and passenger.
In fact, it is impossible to make a complete list of all the factors that can distract the driver from control. In view of this, everyone should be careful about the road, and the habit of not distracting the driver from control will be useful to passengers.
What is the braking distance at speeds of 50, 80 and 110 km / h.
As you can see, because of the many variables, it is impossible to create a clear table that describes the exact braking distance of an individual car. This is influenced by the technical condition of the car, and the quality of the road surface.
Average data of the braking distance of a car with a working system, quality tires and normal driver response:
|Speed, km / h.||Approximate stopping distance, m.|
|50||28 (or six car bodies)|
|80||53 (or 13 car bodies)|
|110||96 (or 24 enclosures)|
The following conditional situation shows why it is important to adhere to the speed limit and not rely on “ideal” brakes. To stop at a pedestrian crossing from a speed of 50 km / h to zero, the car will need a distance of almost 30 meters. If the driver violates the high-speed mode and moves at a speed of 80 km / h, then with a reaction at a distance of 30 meters before the transition, the car will hit a pedestrian. In this case, the speed of the car will be about 60 km / h.
As you can see, you should never rely on the reliability of your car, but it will be correct to adhere to the recommendations, because they are taken from real situations.
What determines the average braking distance of any car
Summing up, we see that the braking distance of any car depends on a combination of such factors:
- vehicle speed;
- machine weight;
- serviceability of brake mechanisms;
- coefficient of adhesion of tires;
- pavement quality.
The stopping distance of the car is also affected by the reaction of the driver.
Given that in an emergency, the driver’s brain needs to process a lot of information, adhere to the speed limit - this is the very first commandment, the importance of which will never stop talking.
1. How to determineb speed along the braking distance? To do this, take into account the type of road surface, the mass and type of the vehicle, the condition of the tires, and the reaction time of the driver.
2. How to determine the speed of a car without braking distance? The driver's reaction time table compares the approximate speed. It is desirable to have a video recorder with speed fixation.
3. What stages does the stopping distance include? The distance traveled during the time when the brakes were applied and also the distance traveled during the steady-state deceleration to a complete stop.