On-road study investigating the mode of feedback delivery on young drivers’ speed management

Feedback has been shown to be instrumental in learning. Refining how it is delivered in driver training has the potential to reduce crash risk. Therefore, the aim of the present study was to examine the effect of the medium in which feedback is delivered (verbal, written, graphical) on young drivers’ speed management behaviour. Sixty young drivers, randomly allocated to one of four feedback groups (i.e., Control, Verbal feedback, Written feedback, and Graphical feedback) completed one training and two test drives using an instrumented vehicle on-road. After the first (baseline) drive, participants were provided feedback about the number of times they exceeded the speed limit, their maximum speed, as well as the financial penalties associated with such driving behaviour, and safety implications. The content of feedback remained the same for all training groups, except for the manner in which the feedback was presented. Verbal feedback was provided verbally by the researcher; written feedback on paper; and graphical feedback using a series of graphs on a computer screen. Control received no such intervention. Two test drives followed, one immediate post-training, and the second one week post-training. Feedback, irrespective of medium improved young drivers’ speed management. Verbal and graphical feedback yielded the greatest reduction in speeding behaviour, with graphical feedback having the most impact in the two speed zones under examination (50 km/h & 80 km/h). Control showed the poorest speed management behaviour in all drives. These findings have important implications for the development of a new approach to improve young drivers’ speed management behaviour.     

Distracted driving caused by voice message apps: A series of experimental studies

Hand-free voice message apps are frequently used by young people while driving. Previous studies have identified voice message apps as a common source of driving distraction. To quantitatively evaluate the factors contributing to driving distractions, three simulated driving experiments were designed using a dual-task experimental paradigm. In Experiment 1, participants completed several common tasks related to voice messages in WeChat with or without manual operations (perceptual-motor distraction). Experiments 2 and 3 further took into consideration the cognitive distraction level, measured by task difficulty and task frequency. The results showed that, in comparison with undistracted driving, the perceptual-motor distraction related to voice message app use significantly (ps < 0.05) weakened young drivers’ driving performance with respect to the standard deviation of lateral position (SDLP) between two cars (0.24 m), response time (0.21 s) and error rate (0.12) to turning lights, and collision percentage (0.54%), similar to the effects induced by non-voice-based apps. There were also significant differences (ps < 0.05) between driving with secondary tasks with and without continuous manual operations in the SDLP between two cars (0.19 m) and in the response time (0.18 s) and error rate (0.10) to turning lights, which indicates that the distracting effect produced by voice-message apps comes from the related manual operations. The effects of cognitive distraction on driving performance mainly depended on task difficulty level. High-difficulty secondary tasks via a voice message app significantly (ps < 0.05) weakened the driving performance in response time (by 0.13 s and 0.13 s compared to low-difficulty and baseline conditions, respectively) and error rate (by 0.07 and 0.07 compared to low-difficulty and baseline conditions, respectively) to turning lights and collision percentage (by 0.90% and 0.80% compared to low-difficulty and baseline conditions, respectively). The findings provide a theoretical reference for analysing the distracting components of voice messages and suggest that drivers should limit the use of these kinds of apps during driving.     

Safety of micro-mobility: Riders’ psychological factors and risky behaviors of cargo TTWs in China

Cargo two- or three-wheeled vehicles (TTWs), as a new form of micro-mobility, have become a popular mode of urban cargo transportation in China. Cargo TTW riders’ psychological factors and risky behaviors lead to a number of accidents. A questionnaire is designed by comprehensively considering these factors and behaviors of cargo TTW riders that includes eleven risk factors to quantitatively analyze the risky behaviors based on structural equation modeling (SEM). One thousand three hundred nineteen participants reported using cargo TTWs on a questionnaire distributed across the country. The characteristics of riding behavior data are analyzed to verify the three-layer risk theoretical framework of “Psychological factors (Personality traits/specific factors) - Psychological acceptability of risks (confidence/perception/attitude) - Risky behaviors”. The results show that anger has a strong direct effect on riding violations, while normlessness and altruism have a direct effect on riding errors. Workload has a weak but direct effect on risky behaviors, and riding feedback has a weak and mixed effect. In addition, high-risk groups are identified by analysis of variance (ANOVA) with rider population attributes. These quantitative analyses can help guide safety countermeasures to mitigate accidents involving cargo TTWs.     

Dual-task decrements in driving performance: The impact of task type,working memory,and the frequency of task performance

Driving while carrying out another (secondary) task interferes with performance, though the degree of interference may vary between tasks and individual drivers. In this study, we focused on two potentially interrelated individual difference variables that may play a role in determining dual-task interference: working memory capacity and the driver’s experience with the relevant secondary task. We used a driving simulator to measure interference, comparing single-task performance (driving alone) with driving performance during three secondary tasks: conversing on a handsfree cellphone, texting, and selecting a song on a touchscreen Mp3 player. Drivers also rated the difficulty of driving while carrying out each secondary task. For the individual difference variables, working memory was measured using the Operation Span test (OSPAN), and experience was assessed in terms of self-reported daily driving exposure and exposure to the relevant secondary tasks (frequency, duration). Overall, we found evidence of dual-task interference, though interference varied between tasks; the texting and Mp3 tasks produced significantly more interference than handsfree cellphone conversation. For the texting and Mp3 song selection tasks, interference was apparent in terms of increased steering variability, but for the Mp3 task there was also compensatory slowing, with drivers slowing down while carrying out the task. OSPAN performance and daily driving exposure were both covariates in predicting the amount of dual-task interference. However, our results suggest that in all but two cases, both involving the texting task, the effects of the OSPAN and the driving and secondary task exposure variables were independent rather than interrelated.     

Correlations of multiple rider behaviors with self-reported attitudes,perspectives on traffic rule strictness and social desirability

Powered Two-Wheeler (PTW) riders constitute a very vulnerable group of road users, while riding a PTW is considerably more dangerous than using any other motor vehicle. Behavioral issues have been identified major moderating factors to PTW crashes, as riders display great variability in their attitudes towards road safety. Τhe aim of this paper is to present a thorough, overarching structure of relationships correlating various unsafe stated PTW rider behaviors (riding after alcohol consumption, speeding, helmet use and texting) with several self-reported attitude parameters and factors regarding rider perspectives on traffic rule strictness and social desirability. A structural equation model (SEM) was developed using data from the ESRA2 survey, which provided a broad sample encompassing 5,958 respondent riders from 32 countries. Numerous statistical relationships were discovered and quantified correlating the four examined unsafe rider behaviors with eight latent unobserved variables. All covariances between unsafe behaviors were found to be positive and statistically significant, indicating that a rider who will engage more frequently in every single one of the four examined unsafe riding behaviors is more likely to also engage in all the others as well.     

Student driver propensity to engage with distractions – a self-report survey

This paper reports a survey of engagement with, and ratings of, driver distraction, for undergraduate student drivers. Survey data was collected using an anonymous online questionnaire. 530 respondents contributed to the survey during a seven-year data collection period.Results indicate that the three internal-to-vehicle behaviours rated as most distracting when driving were ‘writing text messages’, ‘internet use’, and ‘reading text messages’. The three most frequently undertaken distractions were, ‘(interactions with) adults’, ‘daydreaming’, and ‘eating, drinking or smoking’. Considering external-to-vehicle distractions, the top three rated were ‘environmental conditions’, ‘unexpected objects or events’, and ‘animals behaving unexpectedly’; while the most frequently experienced external distractions were ‘people (behaving normally), ‘busy roads’ and ‘official signage’. Some evidence was found that internal-to-vehicle distractions were relatively more distracting than external-to-vehicle ones, along with limited findings showing significant variation in the amount of engagement with distractions over time. Significant predictive models for engagement with distraction were calculated (for both work-related and non-work-related driving) and found to be broadly in agreement with previous research, although accounting for less variance in the models. Significantly greater engagement with distractions was found during non-work-related driving, when compared to work-related.The data present a picture of ongoing and substantial engagement with distracting behaviours for this population over the data collection period. For example, on a daily or weekly basis, more than three-fifths of respondents reported willingness to read text messages with the vehicle in motion; while just under half indicated that they typically write text messages in the same circumstances. However, the findings do offer some promise that interventions targeted towards non-work-related driving behaviours may be effective to reduce volitional engagement with distractions.     

When is the Wilcoxon–Mann–Whitney procedure a test of location? Implications for effect-size measures

The Wilcoxon–Mann–Whitney procedure is invariant under monotone transformations but its use as a test of location or shift is said not to be so. It tests location only under the shift model, the assumption of parallel cumulative distribution functions (cdfs). We show that infinitely many monotone transformations of the measured variable produce parallel cdfs, so long as the original cdfs intersect nowhere or everywhere. Thus there are infinitely many effect sizes measured as shifts of medians, invalidating the notion that there is one true shift parameter and thereby rendering any single estimate dubious. Measuring effect size using the probability of superiority alleviates this difficulty.     

Interval estimation for linear functions of medians in within-subjects and mixed designs

The currently available distribution-free confidence interval for a difference of medians in a within-subjects design requires an unrealistic assumption of identical distribution shapes. A confidence interval for a general linear function of medians is proposed for within-subjects designs that do not assume identical distribution shapes. The proposed method can be combined with a method for linear functions of independent medians to provide a confidence interval for a linear function of medians in mixed designs. Simulation results show that the proposed methods have good small-sample properties under a wide range of conditions. The proposed methods are illustrated with examples, and R functions that implement the new methods are provided.     

Parents’ postnatal depressive symptoms and their children's academic attainment at 16 years: Pathways of risk transmission

The aim of the study was to examine whether parents’ increased postnatal depressive symptoms predicted children's academic attainment over time and whether the parent–child relationship, children's prior academic attainment, and mental health mediated this association. We conducted secondary analyses on the Avon Longitudinal Study of Parents and Children data (12,607 mothers, 9,456 fathers). Each parent completed the Edinburgh-Postnatal Depression Scale at 8 weeks after the child's birth (predictor) and a questionnaire about the mother–child and father–child relationship at 7 years and 1 month (mediator). The children's mental health problems were assessed with the teacher version of the Strengths and Difficulties Questionnaire at 10–11 years (mediator). We used data on the children's academic attainment on UK Key Stage 1 (5–7 years; mediator) and Key Stage 4 (General Certificate of Secondary Education 16 years) (outcome). We adjusted for the parents’ education, and child gender and cognitive ability. The results revealed that parents’ depressive symptoms at 8 weeks predicted lower academic performance in children at 16 years. Mothers’ postnatal depressive symptoms had an indirect effect through children's mental health problems on academic outcomes at 16 years via negative mother–child relationship, and prior academic attainment. There was a significant negative indirect effect of fathers’ postnatal depressive symptoms on academic attainment at 16 years via negative father–child relationship on child mental health. The findings suggest that the family environment (parental mental health and parent–child relationship) and children's mental health should be potential targets for support programmes for children of depressed parents.     

Relationships Among Emerging Adult Psychological Problems,Maltreatment, and Parental Psychopathology: Moderation by Parent–Child Relationship Quality

Current research supports clear relationships between parental psychopathology, parental maltreatment, and emerging adult child psychopathology. Less research has examined how the role of the parent–child relationship influences these existing associations. The current study tested two models that examined the moderating effect of parent–child relationship quality on parental psychopathology and emerging adult mental health as well as the effect on parental maltreatment and emerging adult mental health. It was expected that high parent–child relationship quality would buffer against the negative effects of parental psychopathology and maltreatment while enhancing the effects of functional parenting characteristics. Participants included 1,452 emerging adults, predominantly Caucasian (73.3%) college students who completed surveys on their mental health, recent experienced maltreatment, and their parents’ mental health problems. Results suggested lowest rates of mental health problems for emerging adults were associated with higher parent–child relationship quality and lower parental psychological problems, whereas negative outcomes were associated with higher parental psychopathology, regardless of parent–child relationship quality. Additionally, physical maltreatment was associated with lower rates of mental health concerns in the context of higher mother-daughter relationship quality. Results emphasize the continuing impact of the parent–child relationship, particularly the mother-daughter relationship, on emerging adults’ mental health. Moreover, the current study demonstrates the continuing influence of parents on their emerging adult children.