Factors influencing the driver's response. What determines the driver's reaction time? Driver reaction time when carrying out an auto-technical examination of an accident
Let's take a look at how individual factors affect the overall driver's reaction time.
When measuring the reaction time of drivers on a device designed in MADI, when the subject, on the command "Attention" (on a car simulator), must press the gas pedal and, when the warning red lamp suddenly lights up, move his foot to the brake pedal as soon as possible and press it, the researchers it was found that the average reaction time of experienced drivers who have driven 50 thousand km is 0.5 - 1.5 s, and for drivers with less experience - 1.0 - 2.0 s.
The reaction time increases with fatigue, sickness and after drinking alcohol. So after 6 - 8 hours of driving, the reaction time increases by 0.1 - 0.2 s.
The reaction time in choleric people, as shown by special studies, turned out to be less than in phlegmatic people, by 25 - 35%, but they have more errors. Since choleric people are more prone to hasty and premature actions.
The reaction time increases in the elderly. According to some studies, at the age of 60, the time for a simple reaction increases by 60-65%, and the time for a complex reaction increases by 31-38%. The latter is explained by the fact that in complex reactions, when it is necessary to choose a solution from a number of possible ones, the professional experience of older drivers affects, who more quickly identify the object on the road that creates an emergency, and better predict the way out of an emergency. The minimum reaction time for drivers in the 40-50 age group is twice that of a 20-year-old driver.
The average reaction time is shorter for men than for women. The time of complex reactions in women increases in the menstrual cycle, which is associated with a weakening of attention and a decrease in muscle tone.
An increase in reaction time is also noted when driving in conditions of limited visibility, especially at night. On average, in the dark, the reaction time increases by 0.6 - 0.7 s. This is due to the fact that in poor visibility it takes more time to perceive objects on the road, which increases the latency period of the reaction.
In the dark, visual acuity sharply decreases, depth vision is impaired, and the field of vision narrows. All this complicates the spatial perception of the driver. Even on a full moon, visual acuity drops by 2 times, and with clouds by 20 times! According to other sources, on a light night, visual acuity decreases to 30-70%, and on a dark night - to 5 or even 3%. The night vision acuity is especially reduced in older drivers. If the average visual acuity at the age of twenty is taken as 100%, then at 40 years old it is 90%, at 60 years old - 74%, and at 80 years old - 47%.
Impairment of depth vision leads to the fact that the driver incorrectly determines the distance to the obstacle that appears on the road, makes mistakes in assessing the width of the road. So, it was found that in the daytime the error in determining the distance to the oncoming vehicle is 5-10% by 100 m, and 25% at a distance of up to 1 km. At night, this error increases 2-3 times.
In addition, the daily biorhythm also affects the reaction time at night. Man in the process of long evolution led an active lifestyle during the day, and slept at night. Therefore, at night all life processes proceed at a lower level, which slows down perception, thinking, and, consequently, psychomotor reactions, the time of which increases on average by 75-100%.
The reaction time also increases with an increase in speed, since when objects move quickly, perception is more difficult and occurs more slowly, which leads to an increase in the reaction time. For example, when the driving speed increases from 50 to 70 km / h, the reaction time increases from 1.1 to 1.7 s.
The reaction time also depends on the road conditions, therefore the average reaction time generally accepted abroad is not the same on different roads. For example, in Switzerland, on motorways with a dividing strip, the average reaction time is 2 s, and on ordinary roads - 1 s. In Australia, in the city - 0.75 s, outside the city - 2.5 s.
The reaction time is also influenced by climatic conditions. An increase or decrease in temperature worsens the driver's well-being and reduces his performance. At high temperature functions of thinking, attention, memory are disrupted, time increases and the accuracy of sensorimotor reactions decreases. As a result, the driver does not notice the change in the traffic situation in a timely manner, is late in performing the necessary control actions, makes mistakes, and gets tired faster.
Thus, it follows from the above that the actual value of the driver's reaction time in most cases will exceed the values used by experts in the production of SATE. It is obvious that the use of a differentiated value of the driver's reaction time in expert practice reduces the objectivity and reliability of the SATE. A forensic expert - a car technician does not have special knowledge in the field of individual psychological qualities of a driver, the influence of stress factors and other circumstances of a psychological nature associated with the personal qualities of a driver as a whole.
Obviously, under such circumstances, if we accept the reference values of the reaction time as the minimum possible in a given TTP, the only answer that the driver does not have the technical ability to prevent an accident can be categorical. Otherwise, the conclusion can only be probable, for example: "the driver of the vehicle could have the technical ability to prevent an accident, if the time of his reaction in this TTS did not exceed the accepted reference value." At the same time, according to the current legislation, the expert has the right and is obliged to inform the person or body that appointed the forensic examination of the need to appoint a comprehensive examination on this issue with the involvement of a specialist in engineering and psychophysiological examinations and setting tasks for him to determine the response time of the driver, depending on specific the circumstances of the traffic situation preceding the accident.
Imperfection of the modern method of determining the reaction time of drivers who hit a pedestrian or collide with another vehicle, due to the hypothesis used by all experts, without exception, about the supposedly the same reaction of all people without exception in a particular road traffic situation, without taking into account the individual characteristics of each individual driver. Nevertheless, if the situation during the auto-technical examination of an accident is not entirely clear, then experts recommend that in addition to the auto-technical examination, an engineering-psychological one should be carried out in order to determine the reaction time of each driver who participated in the investigated accident.
V last years a twofold situation has developed, judges do not like to drag out trials by conducting additional examinations, however, lawyers have the right to insist on raising exactly those questions that they may consider significant, including the response time of the driver. There is judicial practice that allows lawyers to refer to the need for such an examination and to raise questions regarding the driver's reaction time. It is enough to make an appropriate search query on the decisions of the courts, however, the prescription of this practice of conducting engineering and psychological examinations on the territory the former USSR available to the general public can be traced back to 1998, when a similar examination was carried out at the Kharkov NIISE, which established the driver's reaction time, which was 2.5 seconds.
In St. Petersburg, at present, such an examination is carried out by employees of the security laboratory. road traffic LLC "Kit Appraisal". The result of which was the publication of the accumulated over the years of practice "". Studies have shown that most of driver response times are significantly lower than those indicated in the tables used by auto technicians in the 60s of the last century. So, for example, the response time in the table can be 0.8 seconds, when in fact it is 2.4 seconds. This means that the stopping distance of a car under the control of this driver at a speed of 60 km / h increases by 26.6 meters. That can significantly affect the outcome of the driver's guilt case, if it is technically possible to prevent an accident.
It should also be noted that the average response time of a driver is not enshrined in law and cannot be used when conducting auto-technical examinations, however, experts use data from an authoritative institute and refer to their scientific validity. On the other hand, the reaction time of an astronaut may differ from the reaction time of a pensioner and cannot be equated. Also, the SDA does not say about the reaction time or the use of averaged values, therefore the use of tables can cause significant harm to the cause of justice due to the absolute groundlessness of the initial data. Studies carried out on the basis of LLC "Kit Assessment" show that in 95% of cases the driver does not have the proper reaction according to the tabular data, due to the individual psychological and physical characteristics of the body. So, for drivers who drink alcohol moderately, the reaction time can be up to 2.8 seconds, while for drivers who do not drink alcohol at all, the reaction time is much better and reaches an average of 1.5 seconds. Thus, we believe that the driver's lack of reaction according to the tabular data is not a basis for his criminal prosecution.
In expert practice, it is customary to distinguish three components of the process that determine the driver's reaction time:
Time of object detection, which depends on many factors, not only visibility and visibility from the driver's seat, but also weather conditions. So, for example, sun glare can make a pedestrian or a cyclist practically invisible to the driver, which must be taken into account when carrying out an auto-technical examination;
The time during which the driver makes a decision on the actions to be taken in the event of a danger to traffic;
The time from the moment of making a decision to the start of the movement by the driver (motor reaction) by the controls, which is a motor component when conducting engineering and psychological examinations. It has been established by experts that, for example, for elderly people, the motor reaction time is significantly lower (3-5 times) compared to young people.
Experts distinguish between simple and complex sensorimotor responses. What does this mean when carrying out an auto-technical examination? A simple reaction is characterized by acting on a well-known cause in a known way. For example, a simple reaction of the driver will be to press the brake pedal when an obstacle or a pedestrian appears in the movement area of the car; in a more everyday, familiar form, a simple sensorimotor reaction is manifested when a prohibiting traffic light comes on or the stop signals of a car in front are triggered. A complex sensorimotor reaction is characterized by an event for which the driver was not prepared in advance. That is why the assessment of the complexity of the situation on the road requires the automotive expert to be balanced when deciding whether to use the time interval in the calculations for a simple or complex (longer) sensorimotor reaction. In old teaching materials, an interval of 0.3 to 2 seconds is allocated for the reaction time, depending on the complexity of the road traffic situation.
When calculating, as part of an auto-technical examination of the circumstances of an accident, the standard time frames are often used, determined by tabular data, to answer the question whether the driver had the opportunity to predict the likely occurrence of an accident, and also to take all measures to prevent it. A very controversial point, given the above. In most cases, the driver, as a participant in an accident, who was driving a high-risk vehicle, is presented in a very unfavorable light for him. Although even inexperienced experts can sometimes wonder how many visionaries we have on the road, based on a reaction time of 0.3 seconds. During this time interval, you can blink about one and a half times.
For typical road traffic situations, the following time intervals, 0.6 seconds, apply:
The appearance of a pedestrian in the traffic corridor of a car, leaving from behind an object blocking the view following another pedestrian;
Departure into the lane of a car, another vehicle that has the preferential right to travel;
The movement of a pedestrian on the roadway in the driver's line of sight.
In 0.6 seconds, at a speed of 60 km / h, the car has time to drive about 10 meters. Those. the stopping distance in a given road transport situation turns out to be obviously shorter than if the expert operated with real data on the driver's reaction time. So, with a reaction time of 1.5 seconds (which is close to the average), the car manages to drive about 25 meters before the start of braking, and if the question of initiating a criminal case is decided, the difference of 15 meters can very significantly affect the fate of the driver. That is why we strongly recommend calculating the reaction time for drivers in each individual case of an accident individually, which is in no way limited from the point of view of the law.
Imagine a situation when a driver had an objective opportunity to predict the occurrence of an accident, but due to certain circumstances could not determine exactly where and when a dangerous road traffic situation would arise, for example, an obstacle on bad road(as an example, you can use the report on the condition of the Nevsky overpass, or the terrible technical condition of the roads in the Murmansk region). In this case, it is believed that the driver could have foreseen the situation and therefore he could be required to pay more attention to the traffic situation, constant monitoring of all factors and risks of an accident. In this case, a typical mistake autotechnical experts, is to apply a time interval equal to 0.8 seconds. But after all, the ability to predict a dangerous road traffic situation cannot be measured by anything, except for some methodological recommendations, the reliability of which we have already had time to doubt when conducting real auto-technical examinations using special laboratory equipment that sets the driver's reaction time. Here is a list of situations for which 0.8 seconds is usually set for the driver's reaction time:
Changing the direction of movement of the overtaken vehicle in front at the time of overtaking;
Departure of oncoming traffic into the lane for a reverse or opposite direction of movement;
Emergency braking of the vehicle in front being overtaken by the vehicle following it;
Changing the trajectory of the vehicle in front due to the current dangerous traffic situation;
Pedestrian exit in the regulated area pedestrian crossing on the carriageway in front of the car, including at a regulated intersection at a permitting signal of a traffic light or a traffic controller;
The appearance in the driver's field of vision of a pedestrian moving from the curb towards the tramway at the tram stop, including when a pedestrian moves to public transport stops;
The appearance in the driver's line of sight of a pedestrian who has entered the carriageway in the area where crossing the street is allowed if he was moving in a different direction, or left a group of standing people;
In the event of a dangerous road traffic situation, about which the driver was warned by a corresponding road sign.
For road traffic situations in which objects that could create a dangerous situation could be in the driver's field of vision, but the previous road traffic situation did not contain signs of danger, a time interval of 1.0 second is used. In this case, the assumption is taken into account that the driver could not determine in advance the place of occurrence of the danger, while the driver should not be distracted from the traffic situation. Unfortunately, practice shows that it is almost impossible to prove such a picture preceding an accident. However, when conducting an auto-technical examination, assumptions and assumptions are often made that significantly reduce the objectivity of the study.
In order for the carried out auto-technical examination to be as objective as possible, lawyers should pay attention to the following questions that can be put in court for the examination:
- What is the reaction time of a particular driver in a given traffic situation?
- How long is the stopping distance of the vehicle, taking into account the individually set driver reaction time?
- Did the driver have the technical ability to prevent an accident, taking into account his individual, psychophysiological characteristics?
A correctly posed question in court can significantly affect the results of the examination, and we can help you in this matter.
The driver's reaction time is essential characteristic, which determines the level of accident-free traffic. It often happens that it is the speed of making and the correctness of the decision in the event of a threat of an emergency situation, as well as the time of their implementation directly affect the occurrence of an accident.
Interesting! Reaction is the body's response to an external stimulus.
Driver reaction time, definition
The speed of the driver's reaction in the traffic rules is the period of time, the countdown of which begins at the moment the driver detects a potential danger and before the start of taking measures aimed at avoiding the danger. Measures means pressing the brake pedal or turning the steering wheel.
Reactions are divided into simple and complex. Simple reactions include a response to one stimulus. Such an irritant can be the braking of the car driving in front. A complex reaction is a response to several stimuli at once. An example would be a regulated intersection, at which the driver must not only comply with the requirements of the traffic light, but also monitor other vehicles and let pedestrians pass.
Stages of the reaction process
The driver's reaction is divided into three stages:
Situation assessment
In this phase, the driver must constructively assess what is happening. Do not fuss or panic, it can only harm.
Decision-making
The driver must decide what action he should take to avoid an accident.
Reacting
The driver performs the action that, in his opinion, is the most appropriate in this situation.
Important!To achieve the safest possible driving experience, the driver must have a quick reaction to the traffic situation.
Average value, and what determines the driver's reaction time
When the driver gets into an extreme situation, he has a few seconds to understand what is happening and make the right decision. It is generally accepted that the average driver's reaction time is 1 second. To date, during the examination, the standard response time of the driver of 0.8 s is used. However, everything is relative. For example, for normal braking, the driver spends 0.5 s, during which time he transfers his foot from the gas pedal to the brake pedal. In the case of a more extreme situation, for example, you need to make a detour maneuver, control actions are activated, and the time for their implementation increases.
F. ERMAKOV
F. Ermakov, Professor of the Department of Life Safety, Kazan State Agricultural Academy, Doctor of Technical Sciences.
When investigating vehicle collisions with a pedestrian parked cars and various fixed obstacles to the forensic auto-technical expert, and the investigator must decide whether or not the possibility of preventing the accident is possible, and the prosecutor and the judge must make sure that their decision is correct. For this, the expert calculates the stopping distance of the vehicle at the speed set by the investigation or the expert. The stopping distance is compared with the distance at which a pedestrian appeared or there were standing vehicles and stationary obstacles. The investigator, prosecutor and judge must check and evaluate the reliability and objectivity of the initial data used by the expert for calculating the stopping distance and the conclusion of the auto-technical examination.
In calculating the stopping distance of a vehicle, in addition to the speed of its movement, take into account the psychophysiological parameter - the driver's reaction time to danger - and the technical parameters related to the vehicle and road conditions, which, according to the technical literature, have limiting values - the minimum and maximum values. However, during the investigation of road traffic accidents (RTA), such a practice has developed that the calculations of the stopping distance of vehicles involved in the RTA, experts carry out, as a rule, with the average values of psychophysiological and technical parameters.
Investigators, prosecutors and judges, when assessing the reliability and objectivity of expert opinions, often do not pay attention to this, which is primarily due to ignorance of technical issues and misunderstanding of the influence of the limit values of design parameters on conclusions about the presence or absence of the possibility of preventing an accident.
So, the calculated parameters have limiting values - the minimum and maximum values. According to the technical literature, the driver's reaction time to danger ranges from 0.4 to 1.2 seconds. Experts in their calculations take it equal to 0.8 sec. For example, let us point out that the stopping distance of a car on a horizontal section of the road with a dry asphalt concrete surface at a speed of 60 km / h and the indicated reaction times is 36.73, respectively; 43,4 and 50,06 m (50.06 m is more than 45 m). From specified comparison stopping distance of the car with the distance to the pedestrian follows one of the proofs of the driver's guilt or innocence.
Taking into account the fluctuations in the reaction time to danger among different drivers, which leads to a difference in the values of the stopping distance of the car (in our example, up to 36.29%), the investigator must put before the expert the question of establishing the presence or absence of the possibility of preventing an accident, for example, a collision of a vehicle per pedestrian, in two versions - with a reaction time to danger of 0.4 and 1.2 sec. If in both cases the same conclusion is obtained about the possibility of preventing the incident, then it should be used for further investigation. If the conclusions are contradictory, the investigator must appoint a comprehensive engineering and psychophysiological examination, putting on its permission the question of determining the actual value of the response time of this driver to the danger. The appointment of the said expert examination must be requested by the prosecutor when checking the correctness of the termination of the criminal case or approving the indictment. Of course, it would be advisable to do this not at the end of the investigation of the case, but during its course. If necessary, such an examination may be ordered by the court.
The need for this expertise has been proven by our experimental studies of the response time to danger in a large number of car drivers. As a result of the research, it was found that the time of their reaction to danger during a 7 - 8-hour working day has a relative psychophysiological constancy. It has also been proven that the driver's reaction time to danger obeys the law of normal frequency distribution. This allows, according to experimental studies, to determine statistically reliable limit values - the minimum and maximum values of the response time of each particular driver to danger at different probabilities.
The established relative psychophysiological constancy of the driver's reaction time to danger is secured by the patent issued to the author in 1999 for invention N 2134062 "Method for determining the professional suitability of an operator to control moving and stationary objects". It established that the maximum permissible value of the reaction time of vehicle drivers to a hazard with a probability of 0.997 (99.7%) is 1.3 seconds. The driver's reaction time to danger should be determined using appropriate experimental equipment during the initial and periodic medical examinations for the suitability of driving, and its limit values obtained by mathematical processing should be recorded in the medical certificate of the subject along with the indicators of vision, hearing, and the nervous system. and etc.
If, in the calculations of the stopping distance of a vehicle, the value of which is the basis for deciding the presence or absence of the possibility of preventing an accident, take the driver's reaction time to danger equal to 0.7 ... 0.8 sec., Then this provides only 50% confidence that the driver who caused the accident can have such a time; if we take 0.8 ... 0.9 sec., the confidence will be 68%; 0.9 ... 1.1 - 95%; 1.1 ... 1.3 - 99.7%.
The use of the above recommendations in forensic practice will make it possible to make objective decisions on specific road accidents, eliminate errors in identifying the perpetrators.
Russian Justice, N 9, 2001
The driver's reaction time is understood as the time separating the signal about a change in the traffic situation received by the driver's senses and the beginning of their impact on the vehicle controls.
Simple formulation, isn't it? Meanwhile, it almost does not reveal the features of the driver's reaction, the time spent on it in different conditions, as well as in the same situation, but under the influence of different factors. All this you need to know in order to minimize the likelihood of a road traffic accident. Knowledge in this case is truly a force that saves human lives. Complete circuit signal path looks like this. Changes in the traffic situation are perceived primarily by the driver's eyes. (The exception is situations when the source of danger is out of the driver's field of vision; then the decision-making time is counted from the perception by the hearing organs.) the form of a series of actions performed by the driver with the steering wheel, brake pedal, etc. However, the human body is a very complex biological system, and instant transmission of a danger signal through it is almost impossible. Suffice it to mention the time spent processing information in the brain. Now, during the examination, the standard driver reaction time is used, equal to 0.8 s. But real life always strikingly different from theoretical calculations. For example, ideally, for braking, the driver just needs to move his foot from the gas pedal to the brake pedal - and spend no more than 0.5 seconds for this. If you need to go around an obstacle, the control actions will be more difficult, and accordingly, the time to complete them will increase ...
In terms of reaction time, male drivers better than women, - by about 0.05 s. The beautiful halves, however, are ahead in terms of control precision. Age Young people are faster at detecting signals and processing information. However, older people spend less time making the right decisions, and their reaction times are more stable.
Experience, seniority
No knowledge of traffic rules and technology can replace the driver's "experience, the son of difficult mistakes." Experienced driver immediately recognizable by calm, disciplined, confident, sometimes even intuitive driving. The ability to anticipate the situation on the road, acquired over the years, significantly reduces the reaction time of a driver with experience.
Fitness
Regular physical education and sports have a healing effect on the body. As a result, physically fit drivers react more quickly to danger.
Working conditions
Urban traffic is a constant change traffic situation... Therefore, the driver, setting himself up for this in advance, reacts better to a sudden danger than "lulled" by a long and monotonous intercity highway.
Times of Day
Night is a time of limited illumination that even the most intense artificial light cannot compensate for. In addition, nature has adjusted the biological clock of the human body to rest at night. In total, this dulls the driver's vigilance by an average of five. Dawn and twilight times are very insidious in this respect.
Unfavorable weather conditions
Anything that limits visibility on the road - rain, snowfall, fog, dust storm - automatically increases the time it takes the driver to react to driving. Poor tire adhesion to the road surface can instantly bring a harmless situation to a threatening one.
Alcohol
A powerful brake on the driver's reaction time - from double increase and more. Even in small doses. This is enough to commit a crime. For no one has canceled the fact that a drunk person driving is a criminal.
Mobile phone
The same unconditional evil for the driver, like alcohol, - it reduces the reaction to the traffic situation at times. Perhaps the law passed by the State Duma to increase the fine for talking on the phone while driving will change the situation for the better. Although, perhaps, it should have been done immediately, as in the Netherlands: there they are punished with two weeks' imprisonment or a fine of 2,000 euros.
Medicines
There is an impressive list of medications after which driving is contraindicated. (And this should be reflected in the information attached to the drug.) Even seemingly harmless cold remedies and pain relievers can significantly prolong the driver's reaction time. Not to mention psychotropic drugs. But stimulants are no less dangerous: after taking them, temporary excessive excitement is replaced by a sharp decline. In addition, if the driver feels unwell, is it worth driving in this state at all? Fatigue
Another factor under the influence of which it is extremely undesirable to hit the road. For example, physical work (many drivers also have to work as loaders) can increase the reaction time by 0.1 s. Another variant of fatigue is very often recorded in the accident reports - "fell asleep while driving." Long distance truck drivers should note that 16 hours of continuous operation increases response times by 0.4 seconds. Tachographs are called upon to solve this problem, monitoring the time of rest and work of drivers.
Workplace
The better its ergonomics, the better the driver reacts to the traffic situation. A seat for the driver's height, a ventilated cabin, and the absence of distracting objects are the components of an accident-free ride. If the transport is freight, reliable fastening of the load, excluding on the road extraneous noise also contribute to low driver fatigue. Music
A variety of musical scores that create a welcoming, work environment in the cockpit, maintain alertness and reduce fatigue. However, this applies mainly to intercity routes; in the city, music is more of a distraction. And one more thing: the louder the music, the worse the driver's reaction time.
Fragrances
Their action is similar to music. There are relaxing aromas, there are invigorating ones. A well-chosen scent will contribute to the concentration of attention on the road.
The profession of a car driver is one of the most widespread in the world, and at the same time one of the most risky. Every day it requires knowledge of all its subtleties, nuances, ideas about how the body reacts to the variability of the road situation, what factors and how control the driver's reaction time. But without all these components, neither true skill nor driving on the roads of the 21st century without mistakes and emergencies is unthinkable.
