Does traffic congestion increase driver aggression?

In his recent article about aggressive driving, David Shinar proposed that the classical frustration-aggression hypothesis (Dollard, J., Doob, L., Miller, N., Mowrer, O. & Sears, R. (1939). Frustration and aggression. New Haven, CN: Yale University Press) provides a useful tool for understanding driver aggression (Shinar, D. (1998). Aggressive driving: the contribution of the drivers and situation. Transportation Research Part F, 1, 137–160). According to Shinar's (1998) application of the frustration–aggression hypothesis, driver aggression is caused by frustration because of traffic congestion and delays. In the present study, the relationships between exposure to congestion (rush-hour driving) and aggressive violations (DBQ) were investigated in Great Britain, Finland and the Netherlands. Partial correlations showed that the frequency of rush-hour driving did not correlate statistically significantly with driver aggression. Correlations between driving during rush-hour and aggression did not differ in magnitude from those between driving on country roads and aggressive violations. In addition, correlations between exposure to congestion and aggressive violations in countries with large number of vehicles per road kilometre (UK, Netherlands) were not higher than those in a sparsely populated country (Finland). These results from three countries suggest that congestion does not increase driver aggression as directly as suggested by Shinar (1998).     

Being Unimpressed with Ourselves: Reconceiving Humility

I first sketch an account of humility as a character trait in which we are unimpressed with our good, envied, or admired features, achievements, etc., where these lack significant salience for our image of ourselves, because of the greater prominence of our limitations and flaws. I situate this view among several other recent conceptions of humility (also called modesty), dividing them between the inward-directed and outward-directed, distinguish mine from them, pose problems for each alternative account, and show how my understanding of humility captures truths present but exaggerated in several of them. Responding to some problems for my view, including what I call “Driver’s Paradox”(i.e., the strangeness of someone’s proclaiming ‘I’m humble!’), I suggest that some over-ambitious claims about our moral responsibilities may indicate a lack of proper humility. I discuss the relationship of the character trait of humility both to what humiliates and to what humbles, concluding with consideration of the background assumptions against which, and the circumstances in which, humility may reasonably be classified as a moral virtue.

Dimensions of driver anger, aggressive and highway code violations and their mediation by safety orientation in UK drivers

Aggressive behaviour on the roads is reported to be on the increase. This study administered Driving Anger Scale (Deffenbacher et al. (1994). Development of a driving anger scale. Psychological Reports, 74, 83–91.), the Driver Behaviour Questionnaire, and the Driving Skill Inventory to a sample of 270 British drivers. Factor analysis of the Driving Anger Scale items yielded three factors measuring anger generated by the reckless driving, direct hostility and impeded progress by others—contrary to the six subscales found with the original US sample. Younger drivers and low mileage drivers were more likely to exhibit all three types of driving anger, but no differences between male and female drivers were found. In addition, a driver’s safety orientation predicted (negatively) anger evoked by impeded progress and direct hostility whereas self-assessed perceptual-motor skills were positively related to anger generated by impeded progress. Both Highway Code and aggressive violations were significantly related to the anger factors, and, using the procedure by Baron and Kenny (Baron & Kenny (1986). The moderator–mediator variable distinction in social psychological research: conceptual, strategic, and statistical considerations. Journal of Personality and Social Psychology, 51, 1173–1182.), the prediction of violating behaviour (Driver Behaviour Questionnaire) by reported anger was shown to be mediated by the self-assessed safety skill scale but not the perceptual-motor skill scale (Driver Skill Inventory), and moderated by neither. Implications for driver education countermeasures are noted.     

Assessment of proneness to distraction: English adaptation and validation of the Attention-Related Driving Errors Scale (ARDES) and cross-cultural equivalence

Prior research developed the Attention-Related Driving Errors Scale (ARDES), a 19-item questionnaire aimed at evaluating the drivers’ predisposition to attentional error, and also provided validity evidence of ARDES measures across two countries: Argentina and Spain. In the current work we adapt the Spanish version of the ARDES to the English language and the culture, traffic regulations and driving habits of the UK, and then provide new evidence of the cross-cultural equivalence of the scale. First, an improved forward and backward translation design was used to translate the Spanish ARDES into English. A committee-approach review process was also performed during the translation phase to guarantee that the English ARDES was the most appropriate to reflect the language, culture, traffic regulations and driving habits of the UK. Second, the adapted questionnaire was tested on 301 British drivers to inspect its psychometric properties and study the relationships between the ARDES-UK and different socio-demographic variables. In agreement with the previous literature, the results of the factor analysis confirmed a single factor and accounting for 33.84% of the variance. Cronbach’s alpha was equal to .89. The observed pattern of relationships of the scores and the different socio-demographic variables was consistent with previous evidence and support the validity of the adapted questionnaire. For example, the ARDES-UK scores were significantly different between drivers reporting and not reporting traffic accidents with material damage. To conclude with, the translation design and the resulting psychometric suggest the validity of ARDES-UK measures for evaluating the British drivers’ predisposition to attentional error. In addition, the evidence in the current work supports the hypothesis of the cross-cultural stability of the scale across Spain and the UK.     

Evaluating the impact of adaptive signal control technology on driver stress and behavior using real-world experimental data

While the operational and crash reduction benefits of adaptive signal control technology (ASCT) have long been investigated, the impact of this technology on driver behavior and stress is still uncertain. This study evaluated the impact of ASCT on driver behavior and stress in a real-world environment. Participants travelled through two arterial corridors, one equipped with ASCT and the other having traditional time-of-day coordinated signals. Driver stress was measured using a heart rate detector and a perceived stress scale while driver behavior was examined using vehicular trajectory data. Overall, driving behavior improved on the ASCT as compared to the non-ASCT corridor, as indicated by higher speeds and a fewer number of stops on the ASCT corridor relative to the non-ASCT corridor. Repeated measures ANOVA showed a statistically significant reduction in driver heart rate by −10 beats per minute over the ASCT corridor. A similar trend was observed for drivers’ perceived stress, analyzed by Wilcoxon sign ranked test. Driving behavior also showed significant improvement with ASCT presence, and speed was found to be negatively correlated with stress. Furthermore, the participants’ speed was controlled by the two systems i.e. ASCT and non-ASCT as expected. This study provides a significant proof of concept that ASCT can create positive improvements in driver stress and behavior that can be further investigated in the future.     

Safety at first sight? – Manual drivers’ experience and driving behavior at first contact with Level 3 vehicles in mixed traffic on the highway

Soon, manual drivers will interact with conditionally automated vehicles (CAVs; SAE Level 3) in a mixed traffic on highways. As of yet, it is largely unclear how manual drivers will perceive and react to this new type of vehicle. In a driving simulator study with N = 51 participants aged 20 to 71 years (22 female), we examined the experience and driving behavior of manual drivers at first contact with Level 3 vehicles in four realistic driving scenarios (highway entry, overtaking, merging, introduction of a speed limit) that Level 3 vehicles may handle alone once their operational domain extends beyond driving in congested traffic. We also investigated the effect of an external marking via a visual external human–machine interface (eHMI), with participants being randomly assigned to one of three experimental groups (none, correct, incorrect marking). Participants experienced each driving scenario four times, twice with a human-driven vehicle (HDV), and twice with a CAV. After each interaction, participants rated perceived driving mode of the target vehicle as well as perceived safety and comfort. Minimum time headways between participants and target vehicles served as an indicator of safety criticality in the interactions. Results showed manual driver can distinguish CAVs from HDVs based on behavioral differences. In all driving scenarios, participants rated interactions with CAVs at least as safe as interactions with HDVs. The driving data analysis showed that manual driver interactions with CAVs were largely uncritical. However, the CAVs’ strict rule-compliance led to short time headways of following manual drivers in some cases. The eHMI used in this study neither affected the subjective ratings of the manual drivers nor their driving behavior in mixed traffic. Thus, the results do not support the use of eHMIs on the highway, at least not for the eHMI design used in this study.     

Parents’ self-efficacy and the quality of supervised driving practice they provide for their children

Learner drivers must gain supervised driving practice in a wide variety of driving situations to prepare them for independent driving. This study investigated the way that sociodemographic factors, parental self-efficacy and driving self-efficacy of parents are associated with the quality of supervised driving practice they provide to their learner driver children. An online survey was completed by 293 fully licensed parents (female = 86%) of learner (52%) and provisional (intermediate; 48%) drivers from Queensland, Australia. A variable indicating quality of supervised practice was defined based on the understanding that higher frequency and greater variety of driving situations and environments represents higher quality supervised practice. Hierarchical multiple regression was used to analyse parent responses. As predicted, driving self-efficacy was significantly and positively associated with quality of supervised practice. However, no significant association was found between parental self-efficacy and quality of supervised practice. Parent gender and perceived level of involvement were also important predictors of supervised practice quality. The association between previous experience with providing supervised practice and supervised practice quality was unclear. A key implication of this research is that devising methods to improve the driving self-efficacy of parents may contribute to provision of more frequent and varied supervised practice.     

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.     

Psychometric properties of driver self-image inventory for Chinese drivers and its associations with personality and driving style

This study aimed to adapt the Driver Self-image Inventory (DSII, Taubman-Ben-Ari, 2008) to Chinese drivers and examine its relationship with personality traits and driving style. Six hundred forty drivers aged 18–55 years agreed to participate in this study. Measurements included the DSII, a personality scale and a validated Chinese version of the Multidimensional Driving Style Inventory (MDSI). The results of exploratory factor analysis (n = 302) and confirmatory factor analysis (n = 305) yielded a three-factor scale with satisfactory reliability. Significant gender differences were found on the DSII factors, with male drivers scoring higher on the impulsive driver factor and lower on the cautious driver factor than female drivers. The validity of the DSII was supported by significant associations between the DSII factors and personality traits, driving style and number of traffic violations and accidents in the previous 12 months. Moreover, drivers with traffic accidents scored significantly lower on the cautious driver factor and higher on the impulsive driver factor than those without traffic accidents. These findings indicate that the reliability and validity of the Chinese version of the DSII are acceptable.     

Drivers’ and cyclists’ safety perceptions in overtaking maneuvers

Drivers overtaking cyclists on rural roads are a safety concern, as drivers need to handle the interaction with the cyclist and possibly an oncoming vehicle. Improving the maneuver’s outcome requires an understanding of not only the objective, measurable safety metrics, but also the subjective, perceived safety of each road user. Previous research has shown that the perceived safety of the cyclist is most at risk at the passing moment, when driver and cyclist are closest to each other. However, to develop safety measures, it is necessary to know how both road users perceive safety, by understanding the factors that influence their perceptions during the overtaking maneuver. This study measured the perceived safety of drivers in a test-track experiment in Sweden and the perceived safety of cyclists in a field test in Spain. For both drivers and cyclists, we developed Bayesian ordinal logistic regression models of perceived safety scores that take as input objective safety metrics representing the different crash risks at the passing moment. Our results show that while drivers’ perceived safety decreases when there is an oncoming vehicle with a low time-to-collision, cyclists’ perceived safety is reduced by a small lateral clearance and a high overtaking speed. Although our datasets are heterogeneous and limited, our results are in line with previous research. In addition, the Bayesian models presented in this paper are novel and may be improved in future studies once more naturalistic data become available. We discuss how our models may support infrastructure development and regulation, policymaking, driver coaching, the development of active safety systems, and automated driving by providing a possible method for predicting perceived safety.