Task-induced fatigue states and simulated driving performance

States of fatigue are implicated in driver impairment and motor vehicle accidents. This article reports two studies investigating two possible mechanisms for performance impairment: (1) loss of attentional resources; and (2) active regulation of matching effort to task demands. The first hypothesis predicts that fatigue effects will be accentuated by high task demands, but the second hypothesis predicts that fatigue effects will be strongest in "underload" conditions. In two studies, drivers performed a stimulated driving task, in which task demands were manipulated by varying road curvature. In a "fatigue induction" condition, the early part of the drive was occupied by performance of a demanding secondary task concurrently with driving, after which the concurrent task ceased. Post-induction driving performance was compared with a control condition in which drivers were not exposed to the induction. In both studies, the fatigue induction elicited various subjective fatigue and stress symptoms, and also raised reported workload. Fatigue effects on vehicle control and signal detection were assessed during and after the fatigue induction. The fatigue induction increased heading error, reduced steering activity, and, in the second study, reduced perceptual sensitivity on a secondary detection task. These effects were confined to driving on straight rather than on curved road sections, consistent with the effort regulation hypothesis. The second study showed that fatigue effects were moderated by a motivational manipulation. Results are interpreted within a control model, such that task-induced fatigue may reduce awareness of performance impairment, rather than reluctance or inability to mobilize compensatory effort following detection of impairment.     

The role of workload and driver coping styles in predicting bus drivers' need for recovery, positive and negative affect, and physical symptoms

A survey was conducted on a sample of 159 Australian bus drivers to determine the extent to which workload and self-reported driver coping styles predicted their subjective health status. The model that was proposed incorporated the hours spent driving as a measure of workload, both adaptive and maladaptive driver coping styles, and self-report measures of need for recovery (i.e., fatigue), positive and negative affect (PA and NA), and physical symptoms. The results of hierarchical regression analyses revealed that the workload was a significant predictor of drivers' need for recovery, but not of their PA and NA nor of their physical symptoms. Need for recovery was in turn a significant predictor of PA and NA and of their physical symptoms, indicating that it mediates the influence of workload on PA and NA and physical symptoms. Two maladaptive coping strategies added to the prediction of need for recovery, as well as to the prediction of NA, even after controlling for the influence of need for recovery. One adaptive coping strategy added to the prediction of PA. Strategies for management of fatigue in bus drivers should focus on the assessment and remediation of maladaptive coping strategies which impact of drivers' need for recovery, which in turn predicts PA and NA and physical symptoms.     

Driver stress as influenced by driving maneuvers and roadway conditions

Excess stress can influence driving performance and increase crash likelihood. The level of stress can also vary based on different driving conditions. Past research has not differentiated among these conditions, but rather has focused on individual driver differences. The goal of this study is to understand how different driving tasks and roadway conditions may influence the stress perceived by drivers. This was accomplished using data from a survey that assessed drivers’ stress under various road, traffic and weather-related scenarios. Factor analytic techniques were used to find groups of driving scenarios that generate similar stress levels in drivers. The results revealed four scenarios that were categorized in terms of (1) weather, (2) visibility, (3) interactions with other drivers, and (4) driving tasks. Ordered logistic regression models were then used to determine the effect of socioeconomic characteristics, trip behavior, and crash history for different stressful driving scenarios. Increases in stress with these four factors were influenced by age and gender, with females being more likely to report higher levels of stress than males. The effect of age varied in that older drivers generally reported higher stress levels, except when interacting with other drivers. Drivers with a history of crashes reported significantly higher stress levels when there was limited visibility, in adverse weather, and while performing common driving tasks. The results revealed that stress depends not only on driver characteristics, but also on the specific driving environment.     

EEG signal analysis for the assessment and quantification of driver’s fatigue

Fatigue in human drivers is a serious cause of road accidents. Hence, it is important to devise methods to detect and quantify the fatigue. This paper presents a method based on a class of entropy measures on the recorded Electroencephalogram (EEG) signals of human subjects for relative quantification of fatigue during driving. These entropy values have been evaluated in the wavelet domain and have been validated using standard subjective measures. Five types of entropies i.e. Shannon’s entropy, Rényi entropy of order 2 and 3, Tsallis wavelet entropy and Generalized Escort-Tsallis entropy, have been considered as possible indicators of fatigue. These entropies along with alpha band relative energy and (α + β)/δ₁ relative energy ratio have been used to develop a method for estimation of unknown fatigue level. Experiments have been designed to test the subjects under simulated driving and actual driving. The EEG signals have been recorded along with subjective assessment of their fatigue levels through standard questionnaire during these experiments. The signal analysis steps involve preprocessing, artifact removal, entropy calculation and validation against the subjective assessment. The results show definite patterns of these entropies during different stages of fatigue.     

A matter of style? Testing the moderating effect of driving styles on the relationship between job strain and work-related crashes of professional drivers

Different empirical studies suggest that both job strain and driving styles are significant contributors to the work-related traffic crashes suffered by professional drivers. Nevertheless, the current evidence falls considerably short when explaining why driving styles may modify (or not) the relationship between occupational stressors and professional drivers’ safety outcomes. The aim of this study was to examine whether driving styles moderate the effect of job strain on professional drivers’ Work Traffic Crashes (WTCs). This research was performed using the data collected from a sample of 753 professional drivers, responding to a self-report questionnaire on job strain (work stress indicator of the Job Demand-Control model), driving styles and work-traffic safety outcomes suffered in the past two years. Regression-based moderation analyses suggest that the job strain of professional drivers is positively associated with the occupational traffic crashes they suffer, and that such association is stronger in drivers with “reckless & careless”, “anxious”, and “angry & hostile” driving styles. Meanwhile, the “patient & careful” (positive) driving style was not associated with a lower risk of suffering a WTC, nor with a lower vulnerability to stress-related WTCs. The results of this study support the hypothesis that driving styles exert a statistical moderation between the job strain and the occupational traffic crashes suffered by professional drivers. These findings may support the design of evidence-based interventions in both the organizational and individual levels, focused stress-related factors and driving styles as predictors of work traffic crashes.     

Validation of the F-DBQ: A short (and accurate) risky driving behavior questionnaire for long-haul professional drivers

Although the Driving Behavior Questionnaire (DBQ) remains the most known tool for assessing risky road behaviors among motor vehicle drivers, recent studies have raised several concerns on the specificity of both driving task conditions and behavioral repertory of certain segments of the driving population. Among them, long-haul (cargo) professional drivers constitute one of the “intensive driving” groups for which the existing adapted behavioral research tools are still very scarce.PurposeThe aim of the present study was to test and validate the F-DBQ (or “Freight Driving Behavior Questionnaire”), a short version of the DBQ adapted to the occupational driving conditions and typical road risk behaviors of freight drivers.MethodFor this cross-sectional study, a sample of n = 982 Spanish long-haul drivers with a mean age of 48.5 years was used, responding to a questionnaire composed of measures on road risk behaviors (DBQ), fatigue (Checklist Individual Strength – CIS and Need for Recovery Scale – NFR) and job stress (Effort–Reward Imbalance questionnaire – ERI).ResultsThrough competitive Confirmatory Factor Analyses (CFA) with structural equation models, it was found that the F-DBQ has a clear dimensional structure, a fair goodness-of-fit, high factorial weights, internal consistency, convergent and discriminant validity and an improved fit to long haul drivers’ working conditions. Also, both (general and work-related) fatigue and job stress have shown to have a significant role in explaining risky road behaviors of long-haul drivers.ConclusionThe findings of this study support that an abbreviated version of the Driving Behavior Questionnaire (the F-DBQ) can be used to assess traffic violations and errors among long-haul drivers, in consideration of their specific task-related conditions (that qualitatively differ from other groups of drivers), with potential implications on the enforcement of occupational and road safety research.     

Cognitive and personality determinants of safe driving performance in professional drivers

Large truck and bus crashes still cause a high rate of fatalities and costs. Considering that the human factor plays an important role it is obvious that there is great interest in predicting safe driving performance in professional drivers, especially with new technologies emerging to assist drivers. This study uses a modern theoretical framework to assess which psychometric tests are still able to predict safe driving performance in today’s professional drivers under these new circumstances.126 male professional bus drivers completed a standardized digital test battery and three driving exercises. The test battery was used to assess reaction time, concentration, ability to gain an overview, reactive stress tolerance, logical reasoning, and safety-related personality traits. The exercises consisted of an on-road driving test, an obstacle course, and a maneuvering course.The study yielded satisfactory indicators of criterion related validity. It also showed that different tests were relevant for the prediction of safe driving performance in different driving exercises. Contrary to previous research, logical reasoning showed significant effects. The results indicate that in order to assess safe driving performance in professional drivers, a comprehensive assessment with psychometric tests should be recommended.     

“Don’t you know I own the road?” The link between narcissism and aggressive driving

Aggressive drivers can make driving dangerous. Over 50% of traffic fatalities are caused by aggressive driving. This research tests whether narcissists are more aggressive drivers than other individuals. Narcissists think they are special people who deserve special treatment. When they don’t get the special treatment they think they deserve, narcissists often lash out at others in an aggressive manner. Narcissists might think they “own the road” and can drive anyway they want, and that other drivers should get out of their way. In the article, we conduct three studies to test the link between narcissism and aggressive driving. In Studies 1 (N = 139) and 2 (N = 100), Luxembourgish motorists completed a measure of narcissism and a self-report measure of aggressive driving. In Study 3 (N = 60), American university students completed a measure of narcissism and then completed a driving simulation scenario that contained a number of frustrating elements. Several measures of aggressive driving and road rage were obtained. In all three studies, narcissism was positively related to aggressive driving. A meta-analysis found an average correlation of r = 0.35 across the three studies. This research replicates previous research linking narcissism to aggression, and extends it to a driving context.     

Exploration of the effects of task-related fatigue on eye-motion features and its value in improving driver fatigue-related technology

Mental fatigue has been lacked attention in developing eye-tracking fatigue detection system for drivers. However, it has great influence on eye movement which could account for the poor validity of current fatigue detectors only focusing on sleep-related fatigue. This work sought to investigate the influence of two types of task-related mental fatigue on eye movement by examining 8 saccade-based, 3 blink-based, and 1 pupil-based metrics. We propose that two types of task-related fatigue caused by cognitive overload and prolonged underload will induce different physiological responses to eye-motion features. Twenty participants completed a vigilance task before and after a 1-h driving with a secondary task in a virtual simulation environment, while forty participants, divided equally into two groups, finished the same task before and after a 1-h and 1.5-h monotonous driving. T-test was applied to analyse the eye-motion, subjective and vigilance data during vigilance task. We found that overload driving made drivers vigilance ability decrease. The eye metrics showed different changes in underload and overload scenario. The blink duration, the mean velocity of saccade and saccade duration increased after 1-h overload driving, while the pupil diameter decreased. However, none of those changes were observed in 1.5-h underload driving, but saccade duration had a significant increase. The fatigue response to heavy demands over short periods of driving is different from the lighter demands over long periods in terms of eye-motion metrics. Considering mental fatigue in designing an eye-tracking fatigue detection system could possibly improve its accuracy.     

Effectiveness of the compensatory strategy adopted by older drivers: Difference between professional and non-professional drivers

It has been a controversial issue for the effect of ageing population on driving safety. Apparently, drivers’ physiological and cognitive performances deteriorate with age. However, older drivers may compensate for the elevated risk by adjusting their behaviors, known as compensatory strategy. Despite the extensive research on this topic, the compensatory strategy of older professional drivers is not well understood since many studies focused on the differences in compensatory behavior between older and young drivers. Professional drivers tend to be more skillful and able to cope with the unfavorable driving environments, thus presenting a higher capability to mitigate the risk. This study attempts to examine the compensatory behavior and its safety effect amongst older professional drivers, as compared to those of older non-professional drivers, using the driving simulator approach. In the driving simulator experiment, participants were asked to follow a leading vehicle for one hour, and two sudden brake events were presented. 41 (mid-aged and older) drivers completed the driving tests. Each participant was required to complete a car-following test, either under high or low traffic flow conditions. Performance indicators include driving capability (i.e. lateral control, longitudinal control, and brake reaction time) and compensatory behavior (i.e. average speed, and time headway). Additionally, two modified traffic conflict measures: time exposed time-to-collision (TET) and time integrated time-to-collision (TIT) are applied to indicate the traffic conflict risk. The random parameter Tobit models were estimated to measure the association between conflict risk and driver attributes, and random intercept models were used to assess other driving performance indicators. Results show that despite the impaired lateral control performance and longer brake reaction time of older drivers, the likelihood of severe traffic conflict of older drivers is lower than that of mid-aged drivers. Furthermore, though both older professional and older non-professional drivers adopted longer time headway, the reduction in the risk of severe traffic conflict is more profound among the older professional drivers. Such findings suggest that older professional drivers are more capable of mitigating the possible collision risk by adopting the compensatory strategy, as compared to older non-professional drivers. This justifies the existence of compound effect by the compensatory strategy of older driver and better driving skills of professional driver. This research provides useful insights into driver training and management strategies for employers, as older drivers would become a major cohort in the transportation industry.     

Young adult drivers' sensitivity to changes in speed and driving mode in a simple vehicle simulator

The study was done to check replication of changes in sensitivity with a simple simulator as had been obtained in an experiment using the real road situation. Another purpose was to control simulator sickness which could have confounded data from testing with a simulator or in actual driving. Sensitivity of the drivers (72 healthy young adults, M age = 24 yr., SD = 5) while performing the driving task was measured in terms of subjective ratings of simulator sickness and affect, and physiological measures (i.e., galvanic skin responses and skin temperature) at different driving speeds and in driving mode conditions, using a simple vehicle simulator. Analysis showed measures of drivers' state, including simulator sickness, physiological indices, and subjective reports, increased with driving speed (30 --> 90 -->120 km/hr.) and driving mode change from the regular speed to sudden increasing to sudden decreasing speeds. Particularly, the results suggest that the increased autonomic nervous activation induces increase of rated simulator sickness. Based upon the same tendency in change of the simulator sickness and physiological state with driving speed and driving mode conditions, it was concluded that, if the results obtained from the simulator experiment can be generalized to the real situation, the simulator sickness must be considered a confounding factor. The results also suggest that the changes in human sensitivity are dependent upon aspects related to speed of a vehicle and driving mode.     

趣味性听觉材料对驾驶疲劳的作用：来自EEG的证据

疲劳驾驶是诱发交通事故的重要因素,研究驾驶疲劳的有效干预方法具有重要意义。本研究通过让驾驶员在驾驶模拟器中完成1小时的单调驾驶任务来诱发驾驶疲劳,同时记录驾驶员主观疲劳、驾驶绩效和脑电θ波功率,来探究趣味听觉材料是否可以缓解驾驶疲劳。结果发现,在单调驾驶条件下收听趣味听觉材料的驾驶员脑电θ波功率高于控制组,表明收听趣味听觉材料不利于缓解驾驶疲劳。     

Investigating the effectiveness of perceptual treatments on a crest vertical curve: A driving simulator study

Rural roads are characterized by a high percentage of run-off-the-road accidents and head-on collisions, mainly caused by inappropriate speeds and failure to maintain a proper lateral position along the roadway alignment. Among several road safety treatments, low-cost perceptual measures are considered an effective tool, as they generally increase the risk perceived by drivers, or even alter the drivers’ speed perception, and consequently tempting them to decrease their speeds. Their effectiveness has been widely recognized in a number of studies, especially with respect to road intersections and curves.The overall aim of this study is to investigate the effects of different perceptual treatments on driving speed, along a crest vertical curve of an existing two-lane rural road, in order to identify the most effective measure to reduce speed and define its subsequent implementation in the field. Three perceptual treatments were tested using a driving simulator: white peripheral transverse bars, red peripheral transverse bars and optical speed bars, with each one being painted along the approaching tangent to the crest vertical curve. The effects of these speed-reducing measures were investigated using a sample of forty-four participants, by comparing the driving speeds with those recorded under a baseline condition (without a treatment); these were also used to validate the driving simulator’s speed measurements with those found in the field. Moreover, subjective measures were collected, consisting of the driver’s static evaluation of the desired speed, risk perception and markings comprehension, based on screen shot pictures that represented the simulated configurations of the treatments.The findings demonstrated an overall effectiveness of the perceptual treatments, although only the red peripheral transverse bars were found to significantly reduce the driving speeds (−6 km/h). The analysis of the questionnaire yielded interesting information and demonstrated the importance of performing driving simulation tests for evaluating the effectiveness of perceptual treatments.Finally, the results confirmed the enormous potential of using driving simulators to pinpoint a number of speed-reducing measures, and consequently select the most effective one that reduces cost and promotes safety before its actual implementation in the field.     

Development of the HIV/AIDS Stress Scale

Development of a self-report measure of stress specific to HIV/AIDS is needed to advance our understanding of the role of stress in adaptation to HIV/AIDS; hence, the aim of this study was the development of the HIV/AIDS Stress Scale. A total of 132 homosexual/bisexual men with HIV/AIDS were interviewed and completed the HIV/AIDS Stress Scale and measures of coping strategies, appraisal, social support and adjustment (global distress, depression, social adjustment, number of HIV symptoms, and subjective health status) at three time points. Thirty-nine primary caregivers were interviewed and completed measures of stress and adjustment. Exploratory factor analyses of the HIV/AIDS Stress Scale items revealed three factors: Social, Instrumental and Emotional/Existential Stress. Factors had adequate internal reliabilities and were stable over 12 months. Construct validation data are consistent with recent stress/coping research that links higher levels of stress with more HIV symptoms, reliance on emotion-focused coping, lower social support, poorer levels of adjustment and higher levels of caregiver stress. Results extend this research by revealing new differential relations between various stress dimensions and stress/coping variables. Convergent validation data suggest that the HIV/AIDS Stress Scale shares conceptual similarity with threat appraisal, and differs from controllability and challenge appraisals. The HIV/AIDS Stress Scale shows potential for the elucidation of the role of stress in coping and adaptation to HIV/AIDS and disease progression in both research and clinical applications.     

Factors in the fatigue of heavy vehicle drivers

This study assessed work-related and driver-related factors in fatigue among Finnish heavy vehicle drivers. 683 professional drivers responded to a questionnaire, 27.8% of whom reported often feeling fatigue during their work shifts. Of the respondents, 27.5% reported having momentarily fallen asleep at the wheel while driving during the past year. Almost half (46.8%) of the fatigued drivers estimated the reasons for momentarily falling asleep were work-related. Long working shifts and short sleeps significantly increased the risk of momentarily falling asleep at the wheel. The risk of fatigue was the highest for the drivers who were unable to choose the time of their breaks.     

Personal factors related to compassion fatigue in health professionals

This study examines the role of some personal and professional factors in compassion fatigue among health-care professionals. Research participants included 182 (89 mental and 93 medical) health-care professionals who completed an assessment battery measuring compassion fatigue, emotion management, trait emotional intelligence, situation-specific coping strategies, and negative affect. Major findings indicate that both self-report “trait” emotional intelligence and ability-based emotion management are inversely associated with compassion fatigue; adaptive coping is inversely related to compassion fatigue; and differences exist between mental and medical professions in emotional intelligence, coping strategies, and negative affect. Furthermore, problem-focused coping appears to mediate the association between trait emotional intelligence and compassion fatigue. These findings shed light on the role of emotional factors in compassion fatigue among health-care professionals. Beyond enhancing our knowledge of practitioners' professional quality of life, the current study serves as a basis for the early identification of groups of practitioners at risk for compassion fatigue.     

Use of rest breaks and accidents by professional drivers

This study examined the effect of rest breaks on traffic accidents by 720 randomly selected professional drivers who completed a postal questionnaire. Drivers involved in an accident preferred to enjoy their breaks at rest places meant for professional drivers, whereas accident-free drivers chose more freely the timing of their breaks during driving.     

Measuring drivers’ takeover performance in varying levels of automation: Considering the influence of cognitive secondary task

Mixed control by driver and automated system will remain in use for decades until fully automated driving is perfected. Thus, drivers must be able to accurately regain control of vehicles in a timely manner when the automated system sends a takeover request (TOR) at its limitation. Therefore, determining the factors that affect drivers’ takeover quality at varying levels of automated driving is important. Previous studies have shown that visually distracting secondary tasks impair drivers’ takeover performance and increase the subjective workload. However, the influence of purely cognitive distracting secondary tasks on drivers’ takeover performance and how this influence varies at different levels of automation are still unknown. Hence, a 5 (driving modes) × 3 (cognitive secondary tasks) factorial design with the within-subject factors was adopted for this driving simulator experiment. The sample consisted of 21 participants. The participants’ subjective workloads were recorded by the NASA-Task Load Index (NASA-TLX). Results showed that compared to manual driving conditions, the drivers’ subjective workloads were significantly reduced in both partially and highly automated driving conditions, even with a TOR, confirming the benefit of the automated driving system in terms of reducing the driving workload. Moreover, the drivers exhibited a lower takeover behavior quality at high levels of automation than manual driving in terms of increased reaction time, abnormal performance, standard deviation of lane position, lane departure probability, and reduced minimum of time to collision. However, at the highly automated driving condition, the drivers’ longitudinal driving safety and ability to follow instructions improved when performing a highly cognitive secondary task. This phenomenon possibly occurred because automated driving conditions lead to an underload phenomenon, and the execution of highly cognitive tasks transfers drivers into moderate load, which helps with the drivers’ takeover performance.     

The influence of an esports-adapted coping effectiveness training (E-CET) on resilience,mental health,and subjective performance among elite league of Legends players: A pilot study

ObjectiveThis study aimed to develop, and pilot esports-adapted coping effectiveness training (E-CET) and measure its influence on coping effectiveness (global and specific), subjective performance, mental health (psychological distress and wellbeing), and resilience.DesignFive elite male League of Legends players competing in the League of Legends Circuit Oceania participated in a mixed methods research design. The effects of E-CET were measured using a within-subjects quasi-experimental design (i.e., pre-to-post, no control group). To measure the effects of E-CET on specific stressors, a longitudinal diary design was used.MethodPlayers participated in a 2-h session of E-CET and a 45-min follow-up workshop. The 2-h workshop delivered content on two conceptual areas: (1) developing awareness of the stress and coping process; and (2) how to cope with stress. Players completed pre-intervention, post-intervention, and follow-up measures and twice-weekly stress journals.ResultsE-CET led to increases in players' perceived coping effectiveness and subjective performance, but there were no changes in psychological distress, psychological wellbeing, and resilience. However, the results indicate some positive signs for future coping interventions with League of Legends players and iterations of E-CET.ConclusionThe E-CET program appears to provide an opportunity to improve performance and mental health for esports players.     

The effect of sleep-need and time-on-task on driver fatigue

Both sleep- and task-related factors are thought to contribute to driver fatigue, with each factor individually associated with deteriorated driving performance. However, the relative and combined effects of these factors in the context of monotonous driving have not been well studied. This study (N = 60) investigated lateral and longitudinal vehicle control, subjective fatigue and physiological response (EEG) during three 10-minute periods of time-on-task spread across a monotonous, 2-hour simulator drive. Level of physiological sleep-need was manipulated between participants by varying the instructed time spent in bed on the night before testing (≤5h or ≥ 8 h). In addition, half of the participants in each sleep group read the applicable speed limit from periodic roadside signs whereas the others performed an arithmetic calculation, displayed on the signs, to determine the speed limit. This task manipulation has been demonstrated to reduce performance decrements over time. Results demonstrated effects of time-on-task and sleep need on self-report ratings, an effect of time-on-task on EEG indices, and an interaction of sleep-need and time-on-task on an EEG index of mental workload and on the lateral control measure of driving performance. There were no significant effects on the measure of speed variability. These results confirm that both sleep-need and time-on-task negatively affect driver state, and that time-on-task decrements in driver performance can occur in the absence of heightened sleep-need. Results also suggest that drivers with heightened sleep-need could protect their performance for a short time, perhaps by exerting effort to compensate for reduced capacity. The secondary task did not counteract declining performance.