The influence of alcohol (0.5‰) on the control and manoeuvring level of driving behaviour,finding measures to assess driving impairment: A simulator study

ObjectiveThe influence of psychoactive substances on driving performance and traffic safety has been extensively studied. Research on the influence of alcohol at the control level of behaviour (i.e. automated processes) has been well established and has shown that the ability to operate a vehicle decreases with rising alcohol levels. However, results one level higher at the manoeuvring level (i.e. conscious processes), are inconsistent. The current study aimed to replicate findings on the influence of alcohol on the control level of behaviour and investigate effects on the manoeuvring level in order to find suitable measures to assess driving impairment.MethodThe study was double-blind, placebo-controlled with a counterbalanced treatment order and a two-way crossover design. Thirty participants performed tasks in a driving simulator under the influence of alcohol (0.5‰) and a placebo. In the driving tasks the control level of behaviour (swerving, average speed, and speed variation) was investigated, as well as the manoeuvring level of behaviour (distance to other traffic during an overtaking manoeuvre, reaction time to a traffic light turning amber, and response to a suddenly merging car).ResultsAs expected, alcohol affected the control level of behaviour negatively. Participants swerved more and showed more speed variation after alcohol intake. The manoeuvring level of driving behaviour was also affected by alcohol. The distance to other drivers during an overtaking manoeuvre was smaller under the influence of alcohol. Results on reaction time were however less straightforward. Reaction time increased significantly under the influence of alcohol when reacting to a traffic light but not in reaction to a car unexpectedly merging into traffic. When analysing behaviour in reaction to these different events in more detail it became clear that they were responded to in varying manners, making it difficult to find an average impairment measure.ConclusionsThe deteriorating effect of alcohol at the control level of driving behaviour was replicated, confirming the suitability of the standard deviation of lateral position and the variation in speed as measures of impairment. At the manoeuvring level, the kept distance to the leading car during an overtaking manoeuvre appeared to be a suitable measure to assess impairment as well as reaction time to a traffic light. The current study also confirms the difficulties in evaluating complex driving behaviour and the need for more research on this subject.     

Mobile phone use while driving-literary review

This paper analysis published results of the research into the connection between mobile phone use while driving and traffic safety. Ever since the introduction of the first mobile phones, the authors have been examining the risks associated with its use in traffic, namely: prevalence or frequency of mobile phone use while driving, characteristics of drivers who make more frequent use of mobile phones, the connection between mobile phone use while driving and a car crash risk, a link between mobile phone use while driving and perception of risk, effects on driving performance of using various modes of mobile phones while driving (“hands-free” or “hand-held”), psychological factors influencing driver's decision to use a mobile phone while driving, etc.It is important to point out that the results of some studies indicate that using a hands-free mobile phone while driving does not provide greater safety as compared to the use of hand-held mobile phones while driving. Generally speaking, younger male drivers tend to use mobile phones more often while driving than women and older males.This paper analyses the results of studies which were published in 60 papers from 1994 to 2013.The analysis of the papers selected for research confirms detrimental effects of mobile phone use while driving. Also, four phases in the process of understanding the issue of mobile phone use impacts while driving have been established or identified. The first phase gives the analysis of the prevalence or frequency of mobile phone use while driving. The second phase identifies the characteristics of drivers who tend to use mobile phones more frequently while driving. The third phase concerns research into impacts of using different modes of mobile phones while driving on driving performance (“hands-free” or “hand-held”). Finally, the fourth phase deals with research into risks of mobile phone use while driving (“hands-free” or “hand-held”). The importance of this paper is reflected in that it can help traffic safety policy makers, on the basis of better understanding of the issue of mobile phone use impact while driving, to develop effective strategies aimed at reducing the extent of mobile phone use while driving.     

Driving distraction at night: The impact of cell phone use on driving behaviors among young drivers

Currently, young drivers are more likely than other drivers to use cell phones while driving at night, which has become a major cause of road crashes. However, limited attention has been given to distracted nighttime driving. Therefore, the aim of this study was to explore the interaction effect of cell phone use and time of day (daytime and nighttime) on young drivers’ car-following performance. Forty-three young drivers engaged in a driving simulator experiment with a within-subject design that included three distractions (no distraction, talking and texting on a cell phone) and two times of day. This paper applied non-parametric tests to analyze the data and obtained the following results: (1) the standard deviation of lane position (SDLP) did not significantly differ at either time of day under no distraction, but it was significantly higher at night on straight roads and large-radius curves after introducing distractions. In addition, participants drove faster and gave less headway on small-radius curves under both distractions at night; (2) texting significantly increased the SDLP, while there was less lateral variation during the talking tasks than under no distraction on simple road sections; and (3) compared with the experienced drivers, the novice drivers drove faster during the talking tasks on small-radius curves, but there was no significant difference between groups during the texting tasks. These findings provide both theoretical and practical implications for related policy makers to enhance traffic safety.     

Intraindividual variability in driving simulator parameters of healthy drivers of different ages

Intraindividual variability is a fundamental behavioural characteristic of aging but has been examined to a very limited extent in driving. This study investigated intraindividual variability in driving simulator measures in healthy drivers of different ages using the coefficient of variation (COV) as a variability measure. Participants were healthy volunteers who were regular drivers, who were divided into a “young” group, a “middle-aged” group, and an “old” group. They drove in two environments (rural, 72 drivers; urban, 60 drivers), under conditions of moderate and high traffic load, without and with distraction (conversation). Significant differences in COV were observed in the rural condition for headway distance and lateral position as a function of traffic load, with high traffic (without and with distraction) resulting in increased COV of headway and decreased COV of lateral position. Significant differences in COV were observed in the urban condition for headway distance only, with high traffic (without and with distraction) resulting in increased COV of headway. No age effects were found for any of the driving conditions. The results indicate that traffic load affected headway distance and lateral position in opposite directions in all three age groups: high traffic resulted in increased variability of headway in both rural and urban conditions but in decreased variability of lateral position in the rural conditions compared to moderate traffic irrespective of distraction. The study indicates that driving conditions affect the intraindividual variability of driving measures in selective ways, which may be linked to the extent of automatization of the driving variables and to adaptive changes to traffic condition challenges.     

Narrow lanes and their effect on drivers’ behaviour at motorway roadworks

In recent years, more use of narrow lanes as a temporary traffic management scheme (TTMS) on UK motorway roadwork sections has been made. The rationale is to free up carriageway space, especially for sites with high traffic demands needing repairs. What remains to be determined is the impact of this work on traffic operation. This is important due to the need to manage traffic operational turbulence which could affect the capacity as well as safety levels in roadwork sections. Site observations (mainly using camcorders from overhead bridges) were made which uncovered two discernible patterns of driving behaviour where narrow lanes are implemented at roadworks, especially when heavy goods vehicles (HGVs) are present: (i) “avoiding” passing/overtaking HGVs travelling in the adjacent lanes and (ii) lane “repositioning” while passing/overtaking which might cause some turbulence to traffic operation. From one site, almost half of the passenger car drivers (including small vans) who were following a HGV on the adjacent lanes were avoiding passing that HGV. Also, nearly three quarters of the observed passenger cars, the passenger car drivers tried to position their vehicles as far away as possible, laterally, from the adjacent HGV while passing/overtaking that HGV in order to widen the lateral gap between their vehicles and the HGV. This resulted in driving too close to the edge of the road markings of their current lane away from the HGV. Therefore, this paper aims to report on the “avoiding” and lane “repositioning” behaviours to help inform traffic management teams/designers using narrow lanes as TTMS and make them aware of such behaviours (especially for motorway sections carrying high percentages of HGVs). Also, the finding from these observations were used in the development of a new micro-simulation model in order to evaluate the effect of such turbulence.     

How drivers adapt their behaviour to changes in task complexity: The role of secondary task demands and road environment factors

The present study investigates the impact of different sources of task complexity such as driving demands and secondary task demands on driver behaviour. Although much research has been dedicated to understanding the impact of secondary task demands or specific road traffic environments on driving performance, there is little information on how drivers adapt their behaviour to their combined presence. This paper aims to describe driver behaviour while negotiating different sources of task complexity, including mobile phone use while driving (i.e., calling and texting) and different road environments (i.e., straight segments, curves, hills, tunnels, and curves on hills). A driving simulator experiment was conducted to explore the effects of different road scenarios and different types of distraction while driving. The collected data was used to estimate driving behaviour through a Generalized Linear Mixed Model (GLMM) with repeated measures. The analysis was divided into two phases. Phase one aimed to evaluate driver performance under the presence and absence of pedestrians and oncoming traffic, different lanes width and different types of distraction. The second phase analysed driver behaviour when driving through different road geometries and lane widths and under different types of distraction. The results of the experiment indicated that drivers are likely to overcorrect position in the vehicle lane in the presence of pedestrians and oncoming traffic. The effect of road geometry on driver behaviour was found to be greater than the effect of mobile phone distraction. Curved roads and hills were found to influence preferred speeds and lateral position the most. The results of this investigation also show that drivers under visual-manual distraction had a higher standard deviation of speed and lateral position compared to the cognitive distraction and the non-distraction condition.     

Using traffic light information as navigational cues: implications for navigation system design

There are compelling research findings that using landmarks such as traffic lights as navigation cues can enhance the acceptability, usability and safety of vehicle navigation systems. In this study, 30 participants undertook an on-road trial using simulated navigation instructions that omitted any reference to distance-to-turn, and instead incorporated information requiring drivers to count traffic lights and pedestrian lights. The study results confirmed that traffic lights can be used as navigation cues even when the density of traffic lights along a stretch of road is high and that the term “set of traffic lights” results in slightly better performance than “traffic lights” alone. Factors other than density were found to have an effect on navigation performance. More errors were made if the target turn was at a pedestrian light and if the turn was visually complex or concealed. In the absence of a navigation task, most drivers did not differentiate between traffic and pedestrian lights when counting the occurrences and only experienced difficulty in counting when the number exceeded 4. Implications for the design of future navigation systems are highlighted.     

Effects of partial sleep deprivation: A comparative assessment of young non-professional and professional taxi drivers

AimThis study aims to determine the effects of partial sleep deprivation (PSD) on driving performance of professional and young non-professional drivers.MethodsThe study included fifty participants (20 professional taxi drivers and 30 young non-professional drivers) driving the simulator-cab in three conditions. The first test session (TS1) was conducted after one night of PSD followed by the second test (TS2) after two consecutive nights of PSD. The driving performance metrics in two conditions of PSD (i.e., sleep duration = 4.25 ± 0.5 h) were compared with the baseline drive with no sleep loss. Sleep restriction was monitored using Actiwatch. Drivers subjectively self-reported their alertness using Karolinska Sleepiness Scale (KSS). Driving performance metrics and reaction time to emergency events were collected during each drive.ResultsA preliminary mixed-design ANOVA showed deterioration in driving performance of all drivers in terms of speed (p < 0.1), speed variability (p = 0.06), standard deviation in lateral positions (SDLP) (p < 0.001) and delayed reaction time (p < 0.05). Separate Mixed-Effects Generalized Linear Models for professional and non-professional drivers showed that speed variability, SDLP and reaction time increased from baseline during both the PSD tests, among both the driving groups. The speed variability, SDLP and reaction time of professional drivers differed significantly from other drivers under PSD conditions. Contrary to the existing belief, the professional drivers had significant decrements in driving performance due to PSD.ConclusionA critical and comparative analysis revealed that driving experience/skill of professional drivers does not improve their resistance to deteriorating effects of sleep loss.     

Towards a new approach to detect sleepiness: Validation of the objective sleepiness scale under simulated driving conditions

The Objective Sleepiness Scale (OSS) was developed to detect and quantify sleepiness on the basis of two direct and reliable sleepiness indicators: EEG and EOG. The present study aims to test whether the OSS can be used to detect sleepiness episodes that impair performance on driving and vigilance tasks accurately and with a good time synchronization. Forty-three healthy volunteers performed monotonous driving sessions on a simulator and the psychomotor vigilance task (PVT) in a normal sleep condition and after partial sleep deprivation. OSS reliability and time synchronization for sleepiness detection were tested on driving (standard deviation of vehicle lateral position and off-road duration) and PVT (reaction time and lapses). Inter-rater reliability of the scale was evaluated by two blinded scorers. Results show that the OSS score indicates higher sleepiness in sleep deprivation conditions (p < 0.001) and with time-on-task. Differences of performance between OSS score calculated with multiple pairwise comparisons, indicate OSS score increase when driving performance (SDLP and off-road duration) decreases (p < 0.001 for comparisons between OSS stages 0 vs 2, 0 vs 3, 1 vs 2 and p < 0.05 for 1 vs 3). Reaction time during PVT is also related to the OSS score (p < 0.05 for OSS values from 0 to 2, 0 to 3, 1 to 2 and 1 to 3). There is no proportional relation between OSS score and performance impairment, but a threshold effect between levels 1 and 2 of the scale is observed. Positive outcomes are also obtained for time synchronization of the OSS assessed on driving performance (p < 0.001 for both SDLP and off-road duration). Finally, inter-rater agreement is found to be considerable. The results allow us to consider using the Objective Sleepiness Scale as a tool for research on sleepiness.     

Being of “two minds”: Assessing vacillating and simultaneous ambivalence with the density matrix

Ambivalence is a common experience that permeates a broad range of research. Unfortunately, quantifying ambivalence has proven a daunting task, with researchers limited to studying vacillating ambivalence, VA (i.e., temporal oscillations between favor/disfavor evaluations of an attitude object). Here, we demonstrate the use of the density matrix to measure both VA and what we term “simultaneous ambivalence” (SA): ambivalence that manifests itself as “in the moment” concurrent favor/disfavor evaluations. In a methodological study we gave participants the option of either single-responding or double-responding to questionnaire items regarding a controversial topic (i.e., affirmative action). Since standard statistical procedures provide no means for analyzing double responses, such data are routinely treated as “bad.” As demonstrated here, the density matrix provides an unambiguous and relatively easy means of accounting for double responses, which is our indicator of SA. Our data are well explained by a mixture model, with participants divided into two nearly equal groups of SA and non-SA participants, and provide evidence that the general phenomenon of SA transcends differences of gender and ethnicity. Further, the density matrix data are consistent with viewing SA and VA as distinct ambivalence constructs.     

The recovery of identity and relative position from visual input: Further evidence for the independence of processing of what and where

Four experiments examined the manner in which item identity and relative position are recovered from visual input. A successivesame/different matching paradigm was designed in which each trial contained a prime and a target display. Each display contained a reference object (i.e., a “+”) and a located object (i.e., a letter, which fell to either the right or the left of the “+”). In Experiment 1, subjects carried out identity judgments on the letters. Experiment 2 examined relative position judgments; in Experiment 3, subjects had to judge both item identity and relative position information. Overall, these initial data suggested that identity and positional information are recovered via independent mechanisms and that these operate concurrently. This suggestion was supported by the results of Experiment 4, which in turn disconfirmed an alternative response account of performance.     

Comparative assessment of the behaviour of drivers with Mild Cognitive Impairment or Alzheimer’s disease in different road and traffic conditions

The objective of this research was the analysis of the driving performance of drivers with Mild Cognitive Impairment (MCI) or Alzheimer’s disease (AD), in different road and traffic conditions, on the basis of a driving simulator experiment. In this experiment, healthy “control” drivers, patients with MCI, and patients with AD, drove at several scenarios at the simulator, after a thorough neurological and neuropsychological assessment. The scenarios include driving in rural and urban areas in low and high traffic volumes. The driving performance of healthy and impaired drivers was analysed and compared by means of Repeated Measures General Linear Modelling techniques. A sample of 75 participants was analysed, out of which 23 were MCI patients and 14 were AD patients. Various driving performance measures were examined, including longitudinal and lateral control measures. The results suggest that the two examined cerebral diseases do affect driving performance, and there were common driving patterns for both cerebral diseases, as well as particular characteristics of specific pathologies. More specifically, cognitively impaired drivers drive at lower speeds and with larger headway compared to healthy drivers. Moreover, they appear to have difficulties in positioning the vehicle on the lane. The group of patients had difficulties in all road and traffic environments, and especially when traffic volume was high. Most importantly, both cerebral diseases appear to significantly impair reaction times at incidents. The results of this research suggest that compensatory behaviours developed by impaired drivers are not adequate to counterbalance the direct effects of these cerebral diseases on driving skills. They also demonstrate that driving impairments increase as cognitive impairments become more severe (from MCI to AD).     

Substance Use and Health and Safety among Homeless Youth

This study examines how substance use is associated with the health and safety of homeless youth using cross-sectional, self-report data from 285 homeless adolescents. Path models were used to examine concurrent relationships between youth’s substance use and multiple aspects of their health and safety, including measures of psychological distress, housing risk and instability, and medical problems. Substance use was examined with both global (i.e., a composite of days of use across various drugs and alcohol) and specific (i.e., rates of use of specific drugs, injection drug use) measures. After controlling for demographic and historical variables, number of days of use was significantly related to psychological distress, whereas injection drug use was significantly related to housing risk. Examination of specific drugs revealed relationships between psychological distress and the use of alcohol, cocaine, and amphetamines, and a specific relationship between housing risk and the use of heroin. None of the measures of substance use was significantly related to youth’s medical problems. Implications for interventions with homeless adolescents are discussed.     

WITNESS AGREEMENT AND THE TRUTH‐CONDUCIVENESS OF COHERENTIST JUSTIFICATION

Some recent work in formal epistemology shows that “witness agreement” by itself implies neither an increase in the probability of truth nor a high probability of truth—the witnesses need to have some “individual credibility.” It can seem that, from this formal epistemological result, it follows that coherentist justification (i.e., doxastic coherence) is not truth‐conducive. I argue that this does not follow. Central to my argument is the thesis that, though coherentists deny that there can be noninferential justification, coherentists do not deny that there can be individual credibility.     

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.     

Visual awareness and the levels of processing hypothesis: A critical review

Does a visual percept emerge to consciousness in a graded manner (i.e. evolving through increasing degrees of clarity), or according to a dichotomous, “all-or-none” pattern (i.e. abruptly transitioning from unawareness to awareness)? The level of processing hypothesis (LoP; B. Windey and A. Cleeremans, 2015) recently proposed a theoretical framework where the transition from unaware to aware visual experience is graded for low-level stimulus representations (i.e. stimulus “energy” or “feature” levels) whereas it is dichotomous for high-level (i.e. the perception of “letters”, “words” or “meaning”) stimulus perception. Here, we will critically review current behavioral and brain-based evidence on the LoP hypothesis and discuss potential challenges (such as differences in LoP conceptualizations, awareness scale related issues, attentional confounds and divergences on experimental factors or statistical analyses) which might be of use for future research within the field. Overall, the LoP hypothesis is a recent and promising proposal that attempts to integrate divergent evidence on the graded vs. dichotomous emergence of awareness debate. Whereas current evidence validates some of the assumptions proposed by the LoP account, there is still much work to do on both methodological and experimental levels. Future neuroimaging studies might help to disentangle the current complex pattern of results found in LoP studies and, importantly, shed some light on the ongoing debate about the search for the Neural Correlates of Consciousness (NCC).     

TREATMENT ACCEPTABILITY AND “FAKING GOOD”: ARE STAFF TELLING US WHAT THEY THINK WE WANT TO HEAR?

Treatment acceptability refers to how acceptable various treatment alternatives are to individuals who are subjected to and who implement those treatments. While treatment-acceptability research increases in popularity, some have questioned its usefulness. In particular, Schwartz and Baer (1991) question whether staff might be telling us what we want to hear, analogous to the phenomenon of test-takers “faking good” while taking personality tests. In this study, we sought to investigate the possibility of such bias in treatment-acceptability ratings. Direct-care staff at a large residential facility were presented with a clinical vignette and five treatment options to rate. They also received three different types of instructions (standard, “fake good,” and “prompted honesty”) designed to determine whether biases in ratings would appear. Results indicate that, under these conditions, staff do not fake good, i.e., there were no differences across instructional conditions. Collapsing across conditions, staff did differ in their ratings on the five treatment alternatives. Reasons for current results and suggestions for further research are discussed.     

Associations between substance use among car and van drivers in Norway and fatal injury in road traffic accidents: A case-control study

The aim of this study was to determine the association between alcohol or drug use with fatal injury in road traffic accidents by calculating odds ratios (ORs) using a case-control design. The ‘cases’ were 508 drivers killed in road traffic accidents in the period 2003–2010 from whom blood samples were sent to the Norwegian Institute of Public Health for alcohol and drug testing, and the ‘controls’ were 9261 random drivers in normal traffic. Blood samples from ‘cases’ and oral fluid samples from ‘controls’ were analysed for alcohol, 15 drugs which have legislational concentration limits in Norway, in addition to two other commonly detected psychoactive drugs. The ORs for being killed in a traffic crash with blood alcohol concentration above the legal limit of 0.02 g/dL was 199.5 (95% CI 112.6–353.2). For the use of amphetamines without other substances the OR was 41.6 (95% CI 12.6–137.1), and for use of two or more substances 85.0 (95% CI 46.3–156.1). The OR for general use of only one medicinal drug was 6.0, and no significant ORs were found for the specific use of only zopiclone or THC. The ORs were generally higher for involvement in single-vehicle accidents. It is likely that the observed ORs, particularly for alcohol, are not only related to the risk posed by the substance alone, but a combination with behavioural factors, such as sensation seeking or risk taking behaviour.     

Typology of dogs by the conditional reflex method

Some of the problems and concerns which initiated and motivated the development of typological research in Pavlov’s laboratories are reviewed. Explanations are developed as to the basic theme underlying the typing methods. Two outstanding methods of typing dogs, the “large standard” and the “small standard,” are presented in considerable detail. The basic four types that emerge from the testing procedures and some of their shortcomings are discussed. The importance to Western investigators of acquiring a first hand knowledge of this methodology is stressed.