Prof. Dr. Konrad Reschke
Institute for Psychological Therapy e.V., Leipzig
Dr. Udo Kranich
Institute for Psychological Therapy e.V., Leipzig
A driver’s stress, strain and load are terms that have barely been thoroughly investi- gated in the context of increasing traffic safety, avoiding traffic accidents and offences, and further reducing traffic-related deaths. Their relevance for traffic safety and the fur- ther development of a safe multisystem driver-vehicle-traffic interaction is undisputed. In the following discussion, some of the basics of stress, strain and load are discussed in terms of action theory according to Reschke & Schröder (2010), whereas the discussion of general stress theories (e.g. Lazarus, 1966, Lazarus & Launier, 1978, Heinrichs, Stechele & Domes, 2015) has been omitted.
1. The stress concept – Fundamentals of al stress model based on action theory and related to transportation
In the context of transportation, current stress theory states that drivers are equipped with skills (driving ability, driving skills) and needs that enable them to meet the re- quirements of (road) traffic (e.g. with regard to attention, length of driving, occupational tasks, traffic density, traffic conditions, time compliance) and thereby regulate their stress levels themselves. The driver can be supported by various resources, both exter- nal and internal…
The development of motor vehicle technology is basically a resource development that historically assists the driver and constantly tries to improve traffic safety. The develop- ment of a Front Brake Light and all the research carried out on it are also an expression of the effort to increase the safety of multisystem interactions by means of suitable new technical developments.
The relationship between the driver, automotive technology and road traffic is consi- dered to be contradictory in principle as a multi-sensory diversity of requirements for motorists when driving in traffic. It requires ongoing regulatory efforts and further devel- opment at all levels. However, not only technical systems have load limits. Even the capacity of the human psychophysical system is limited and its burden cannot be con- tinually increased. Critical limits (e.g. alertness, attention, driving times, alcohol limits or sensory stimulus density) must be observed and should not be exceeded. On the one hand, legal foundations were created for this purpose. On the other hand, technical, environmental and internal regulatory activities complement the automated responses to requirements by matching (congruence) and balancing (consistency).
The term stress, within the multi-systemic and complex context of the driver-vehicle- traffic system, describes a human psychophysical state of regulation which is relevant for an individual, if the personal human-environment relationship can no longer be com- pensated with behavioural routines and reaction automatisms (Reschke & Schröder, 2010). In the experience of the individual, stress is reflected in the form of need-threat, destabilization, perceptual and information-processing capacities, and stressfulness in coping with demands. Stress thus describes a problem situation that requires a switch from the emotion-controlled behavioural level to cognitively organized and reflected ac- tions.
The psychophysical stress response results from the highly individual interaction of four interacting condition groups (Figure 1). For the individual, above all, their capability structure with basic perceptual and behavioural competencies as well as stress-related coping skills are of importance. These components essentially make up the personality factor, which, with its experience-based and constitutional features, represents a more or less flexible and stable background to coping (driving skills-relevant personality and biopsychosocial competencies, e.g. perception, control and decision-making processes when driving in traffic). Thus, for example, young drivers, who have undergone profes- sional training are less often confronted with skill deficit situations and therefore will act at the limit of their regulatory stability less often than others, such as learner drivers.
Those who have skills for solving problematic regulatory situations also have advan- tages over inexperienced drivers.
At a predominantly instrumental level of behavioural organisation, the stress-relevant discrepancies arise from the relationship between abilities and external requirements. For the analysis and the reduction of stress, strain and load the respective requirement profile and the type of stress in relation to the individual coping possibilities are of impor- tance. It is important to distinguish between stressful long-term requirements and fre- quently recurring events or short-term stress. These factors are formed by external stressors. The intensity, duration, complexity, predictability and controllability of stimuli from the traffic situation determine the mental requirements components.
Any reduction in the complexity of the safety-related signals to be observed and con- trolled is a contribution to stress reduction through preventive interventions. The con- crete contradictions between the illustrated complexes of conditions put the psycho- physical regulatory system of man under pressure. Any attempts to reduce stress by reducing irritation and improving regulation by adding safety-related and control effort- reducing signals can stabilise behaviour and safety in traffic.
Emotional and cognitive assessments identify the onerous situation and provide psy- cho-energetic power including behaviour as well as the corresponding physiological, endocrine, and immunobiological mechanisms. The acute stress reaction is appropriate; it mobilises individuals and makes them capable of responding to a demanding situation.
Chronic stress reactions, on the other hand, represent a permanent overburdening with the risk of destabilising health and performance. The psycho-physical quality of the condition described here is particularly stressful in its chronic form, as are the negative forms of fatigue under excessive demands and monotony when under-challenged.
Fig. 1: Condition groups of the psychobiotic stress response according to Reschke & Schröder (2010)
Starting points of stress management and stress reduction
In the multisystemic, complex traffic space, relative and behavioural interventions to manage stress are possible. The activities of stress management on the external re quirements and relationships (ratio prevention) are based on the objective load side, in traffic by rules, laws and workplace shaping and action-facilitating measures. This includes all technical equipment of the motor vehicle. They have the general objective to change working and living conditions of the road user positively and according to needs, to influence positively traffic safety and activity regulation.
The following explanations therefore relate in particular to the situation design and tech- nical equipment on the motor vehicle, which must allow by clear signal reduction to re- duce stress by security of perception and control. Stress management processes are thus also facilitated by external resources on the vehicle if, for example, these facilitate the perception of and attention to braking from the front, which also increases traffic safety.
2. Stress in traffic
The stress experience of motorists always arises from a combination of personal and environmental variables. Evers (2009) classified these variables in the form of activity- related (environmental variables) and the personal stressors of motorists’ lives. In prin- ciple, road safety issues affect all road users, but professional drivers and high-mileage drivers (taxi drivers, driving instructors, bus drivers, etc.) have special burdens.
In the meantime, a stress management program entitled “Optimistically mastering the stress of driving” has been developed by Reschke, Kranich & Lessing (2015). In addi- tion to an individual stress analysis of the driver, specific modules for stress manage- ment are developed with the participants as well as imparting knowledge on the topic: “Stress in traffic”.
3. Stress reduction by the use of motor vehicle technical facilities
The overall system of transportation consists of the subsystems “human” (driver, road users), “vehicle” (means of transport) and “road” (traffic environment), which interact with each other in many different ways (e.g. Klebelsberg, 1982). Factors such as an increasing traffic density, time and deadline pressure increase traffic conflicts. Traffic situations can be perceived by the road user as threatening, especially if they are not sufficiently predictable from the behaviour of other road users. Klebelsberg (1982) de- fines traffic conflicts as “opposing behavioural tendencies of road users (…) whose di- rection ultimately leads to an accident, but which are counteracted by one or both road users”
More control over behaviour in road traffic can also be achieved through the use of technical means. These may, for example, help to improve/defuse and / or better iden- tify dangerous situations in traffic. This increases the predictability of potential hazards, reducing the sense of threat, which in turn can reduce stress. In particular, the process of information processing is facilitated because the human brain can handle unique sig- nals more easily than ambiguous ones. In particular, it is not capable of simultaneously processing various signals in complex request situations (multitasking). Information processing includes selection, processing and action and takes place at all hierarchical levels of the driving task and driving behaviour, whilst the specific processes depend on the difficulty of the task. A driver learns to detect the signals of driving-relevant stimuli and can decide in the course of his driving experience through automation (learning) on the basis of less safety-relevant stimuli.
For example, Rumar (1985) describes processes of information acquisition and proc- essing that are sequential and controlled by cognitive and motivational factors. Within the information processing process, the information is selected and structured and con- densed. First, environmental information is sensory-selected and processed cognitively (by memory and perception processes) until finally a decision is made which translates into a response by the driver. The cognitive processing processes are guided by atten- tion, motivation, experience and expectation. At the same time, Rumar (1985) assumes that different filter processes influence information processing.
The physical filtering concerns the external physical environment and means that cer- tain stimuli or objects cannot be detected sensorially because they are masked, for ex- ample, by other stimuli or objects (such as sounds). Perceptual filtering may be based on sensory processes and perceptual structuring and means that the attention is di- rected to a stimulus, i.e. attention are more focused on certain stimuli than others. An additional signal element on the vehicle can potentially attract attention. It can be as- sumed that control of the level of safety-relevant attention control can also be increased by technical signals which can provide the road user with important additional informa- tion for the adequate perception of traffic situations.
4. Stress reduction by using the Front Brake Light
Because the Front Brake Light is mounted at the front of the vehicle, this signal is per- ceived by road users other than those for whom the rear brake lights are visible. The Front Brake Light indicates the current braking behaviour of the driver (or of the autonomously driving motor vehicle) and thus facilitates communication with other road users, particularly the more vulnerable ones such as pedestrians and cyclists. There are numerous traffic situations in which it would be important to obtain information about the driving behaviour of a motor vehicle at an early stage (see chapter 4.2).
The use of the Front Brake Light would give other road users an additional stimulus source. It would be easier for them to tell if a vehicle is really decelerating or not. This gain in information minimises the uncertainty and therefore the potential threat in am- biguous or even dangerous traffic situations, and can, therefore, be regarded as a stress-reducing factor.
This assessment is based on the following considerations according to the stress model of Lazarus (1966). The evaluation of a stressor takes place in several steps: First, the situation is assessed as stress-relevant (primary assessment), e.g. experienced as a threat. This is often associated with negative emotions such as fear, anger and anxiety.
The second step (secondary assessment) is to assess one’s own coping skills and op- portunities by weighing up which coping options are available, the probability of their success and the extent to which such strategies are mastered. Experiences of more adequate coping with traffic situations, in this case by the presence of additional infor- mation about the behaviour of other drivers, can then lead to a change in the assess- ment of the initial situation and a decision as to whether more information is required. This can lead to a reassessment of the situation. Coping is defined by Lazarus and Folkman (1984) as a cognitive and behavioural effort designed to reduce, master or tol- erate internal or external demands. In the present case, it can be assumed that external requirements (uncertainty about the behaviour of drivers in road traffic) can be better detected by the use of the Front Brake Light and then managed more adequately.
However, the following must be kept in mind: A generally effective coping strategy does not exist, as “effectiveness” depends on the content and characteristics of the stress situation, on the characteristics of the individuals concerned or on dispositional coping preferences. However, one form of coping strategy has proved to be effective again and again. It is active problem-solving, but, as a strategy, it can only function effectively if the situation can also be considered sufficiently controllable. The use of the Front Brake Light is likely to increase the likelihood of this being so.
Target group specific benefits (e.g. pedestrians, older road users, drivers with special needs)
In principle, many different groups of road users can benefit from the addition of a Front Brake Light.
For pedestrians, in particular, it is not always clear whether or not a car has really initi- ated a braking operation. A classic situation is the pedestrian crossing. In most countries, the approaching vehicle is actually obliged to stop so as to enable the pedestrians to cross the road safely. However, pedestrians receives no clearly recognisable optical signal to indicate to them that the driver really has fulfilled this obligation. They can only observe the behaviour of the approaching vehicle and draw conclusions as to whether or not the driver will really comply with the obligation to stop. However, this scenario is associated with considerable uncertainties. It is a subjective assessment. The pedes- trian has to rely in part on the fact that the motorist will adhere to the rules regarding the use of pedestrian crossings. In addition, studies have shown that pedestrians are often denied priority at the crossing. By using the Front Brake Light; this uncertainty factor could be significantly minimised. By directing their attention to the specific traffic situa- tion, pedestrians would receive an additional clearly identifiable signal (illumination of the Front Brake Light), indicating that the braking process has been initiated. The use of the Front Brake Light would represent an additional component for reducing stress, par- ticularly for the target groups of elderly pedestrians and children, who are more at risk of injury in road traffic.
The use of the Front Brake Light would also have a stress-reducing effect for drivers of emergency or other vehicles with warning signals. These special signals provide war- nings to other road users by means of light and sound signals as specified by the local traffic regulations. Special signals initiated by acoustic and optical devices on vehicles serve to warn against dangers. In cases of emergency, the vehicles of the aid organisations (fire brigade, ambulance service, etc.) only move with blue lights and specified acoustic signals. Once people are in need, the time factor often plays an important role. The faster these vehicles drive, the more effectively the relief measures can be initiated. On their way to help, these drivers must trust that other road users perceive the vehicle with special rights and adjust their behaviour accordingly, for example by giving way to them. This scenario is also associated with considerable uncertainties on the part of the drivers of emergency vehicle. Trips with blue lights and special signals (siren) are among the most dangerous situations in traffic. By using a Front Brake Light, uncer- tainty factors could be significantly reduced. Drivers of vehicles with special rights di- recting their attention to the specific traffic situation would receive an additional, clear signal giving them indications that other road users have recognised the emergency vehicle, adjusted their behaviour and initiated the braking process, and so contributed to increasing traffic safety.
5. Summary and conclusions
The term “stress” is defined as a state of psychophysical regulation which becomes relevant for the person when the personal human-environment relationship has reached a quality of contradiction that can no longer be compensated for by behavioural routines and reaction automatisms. In the experience of humans, stress is reflected in the form of need threat and destabilisation. Stress refers to a problem situation that requires the sufferer to switch from the emotion-driven level of behaviour to cognitively organised and reflected actions.
The stressful life of motorists always arises from a combination of personal and envi- ronmental variables. In principle, stress in traffic can affect all road users, but special burdens have to be carried by professional drivers and representatives of many profes- sional groups (taxi driver, railroad driver, driving instructor, bus driver, etc.).
Factors such as increasing traffic density, time and deadline pressures can increasingly lead to traffic conflicts. Traffic situations can then be perceived by the road user as threatening, especially if they are not predictable, and behaviour patterns are not always predictable.
The more the road user keeps control in (ambiguous) traffic situations, the less they are perceived as threatening. This in turn can be considered as a stress reducing factor.
More control for road users can also be achieved through the use of technical means such as signals. By implementing the Front Brake Light, uncertainty factors could be minimised in traffic situations that are neither clear nor unambiguous. Examples have been given for the target group of pedestrians and the driver for vehicles with special signals.
The present work is a theoretical derivation. Of course, various stress parameters are now also easily measurable. It is for further studies to provide empirical evidence that the use of the Front Brake Light on vehicles can significantly reduce the stress on road users.