How do the recognizability and driving styles of automated vehicles affect human drivers’ gap acceptance at T- Intersections?

Future traffic will be composed of both human-driven vehicles (HDVs) and automated vehicles (AVs). To accurately predict the performance of mixed traffic, an important aspect is describing HDV behavior when interacting with AVs. A few exploratory studies show that HDVs change their behavior when interacting with AVs, being influenced by factors such as recognizability and driving style of AVs. Unsignalized priority intersections can significantly affect traffic flow efficiency and safety of the road network. To understand HDV behavior in mixed traffic at unsignalized priority T-intersections, a driving simulator experiment was set up in which 95 drivers took part in it. The route in the driving simulator included three T-intersections where the drivers had to give priority to traffic on the major road. The participants drove different scenarios which varied in whether the AVs were recognizable or not, and in their driving style (Aggressive or Defensive). The results showed that in mixed traffic having recognizable aggressive AVs, drivers accepted significantly larger gaps (and had larger critical gaps) when merging in front of AVs as compared to mixed traffic having either recognizable defensive AVs or recognizable mixed AVs (composed of both aggressive and defensive). This was not the case when merging in front of an HDV in the same scenarios. Drivers had significantly smaller critical gaps when driving in traffic having non-recognizable aggressive AVs compared to non-recognizable defensive AVs. The findings suggest that human drivers change their gap acceptance behavior in mixed traffic depending on the combined effect of recognizability and driving style of AVs, including accepting shorter gaps in front of non-recognizable aggressive AVs and changing their original driving behavior. This could have implications for traffic efficiency and safety at such priority intersections. Decision makers must carefully consider such behavioral adaptations before implementing any policy changes related to AVs and the infrastructure.     

Social exclusion affects aggressive driving behaviour: The mediating effect of prosocial tendencies and driving anger

Social exclusion—being rejected or ignored by individuals or groups—is a common and adverse experience in social life. As a social activity, driving behaviour can be influenced by many factors. Whether social exclusion is one of these factors is an open question. Therefore, the aim of this study is to explore the impact of the social exclusion experience on individuals and their driving behaviours and the mediating effect of prosocial tendencies and driving anger. A total of 240 (104 males and 136 females) participants from China completed a questionnaire including the Ostracism Experiences Scale (OES), the prosocial tendencies measure (PTM), the Driving Anger Scale (DAS) and the Driver Behaviour Questionnaire (DBQ). The hierarchical multiple regression analysis and pathway analysis results showed that social exclusion experience and driving anger positively predicted aberrant driving behaviours (including aggressive violations, ordinary violations, lapses and errors), while prosocial tendencies had a negative impact on aberrant driving behaviour. Moreover, prosocial tendencies and driving anger mediated the relationship between social exclusion and driver behaviour, accounting for 11.18% and 46.71% of the total effect, respectively. The chain-mediated effect of prosocial tendencies and driving anger was also significant, accounting for 5.26% of the total effect of social exclusion on driver behaviour. This study examines the mechanisms underlying social exclusion experiences that positively predict individuals' unsafe driving behaviours, thereby filling a gap in social exclusion research and suggesting new avenues of exploration into the personal and social influences that affect driving behaviours.     

The role of trait emotional intelligence in driving anger: The mediating effect of emotion regulation

Emotions during driving have an essential impact on driving safety. This study aims to explore the relationships among emotional intelligence, emotional regulation, driving anger and related behaviour. A total of 304 drivers (aged 18–57) completed online questionnaires, including the trait emotional intelligence (TEI) scale, difficulties in emotional regulation scale (DERS), driving anger scale (DAS) and driver anger expression inventory (DAX). The results showed that the influence of TEI on maladaptive driving anger expression was negative, and individuals with higher emotional intelligence showed less maladaptive expressions of driving anger. Difficulties in emotion regulation played a mediating role between emotional intelligence and driving anger. These results suggest that drivers with high emotional intelligence and emotion regulation may face driving situations calmly and with a high level of driving safety.     

Generating Recommendations for Simulator Design Through Pilot Assessment of Prototype Utility

Incorporated in a simulator design project, this study assessed the utility of a simulator prototype for air combat training to optimize continued development. After several scenarios, the 13 male participants completed a survey. Seven fidelity levels: visual feedback, head-up/head-down, instrumentation, flight controls, graphics, visual resolution, and field-of-view were rated for three dimensions: realism, limitation of performance, and importance of realism. The results informed decisions about which fidelity levels, head-up/head-down and field-of-view, that should be prioritized during the next design cycle, and generated recommendations for continued simulator design and directives for further evaluations.     

Anger-congruent behaviour transfers across driving situations

Anger and aggression on the road may sometimes appear unprovoked and unrelated to current driving circumstances. It is unclear whether such anger and aggression arises because of events prior to those circumstances in which anger is experienced and aggression is exhibited. In this study, time pressure and enforced following of a slowly moving vehicle were used to increase drivers’ anger in order to assess whether affect and behaviour during a subsequent, non-provocative, drive would change accordingly. Ninety-six drivers drove twice in a simulated urban environment. During the first drive, oncoming traffic and a slowly moving lead vehicle required that half of the drivers travelled far slower than they would choose. During the second drive, drivers again followed slower vehicles and were required to respond to traffic events not encountered in the manipulation drive. Mood (Profile of Mood States) was assessed before and after each drive, and anger evaluations, arousal (heart rate) and behaviour (speed, lane position and collisions) were measured during drives. Anger increased and both mood and driving behaviour deteriorated in drivers exposed to slower lead vehicles, compared with control group drivers. These behavioural differences of speed and lane positioning carried over into the subsequent drive even to driving situations unlike those where provocation had previously occurred. Drivers who had previously been impeded later approached hazards with less caution, and attempted more dangerous overtaking manoeuvres. It is concluded that sometimes dangerous driving may result from anger provoked by circumstances other than those in which the behaviour is exhibited.     

Safety implications of co-locating road signs: A driving simulator investigation

BackgroundAs road complexity increases the requirement for number of road signs also increases, although the amount of road side space does not. One practical strategy to address this is to present multiple road signs on the same gantry (sign co-location). However, there is very little research on the safety implications of this practice.Method36 participants (mean age = 42.25 years, SD = 13.99, 18 females) completed three driving simulator scenarios, each scenario had a different sign co-location condition: no co-location, dual co-location and triple co-location. Each scenario presented similar information using direction signs, variable message signs and variable speed limit signs, under. Each drive included standard motorway driving (100 km/h speed zone) in free flow traffic and one emergency event where a lead vehicle suddenly braked. The scenario order was counterbalanced and the emergency event vehicle varied.ResultsOverall, there was no impact of co-locating signs on general driving performance. No significant difference was observed between conditions for reaction time and minimum headway in response to the emergency event. Participants were able to correctly choose their destination whether the signs were co-located or not.DiscussionFor the particular configuration of signs tested there is no evidence that co-location negatively impacts driving performance. However, there may be some implications for travel speed and the manner in which the emergency event is responded to. Future work should confirm the findings on real roads. These findings provided support for sign co-location as a practical and safe option for displaying multiple road signs in a confined area.     

Speed reductions and judgments of travel time loss: Biases and debiasing

Priority decisions concerning maintenance or reconstruction of roads are made with the aim of road improvements with as little traffic disturbance and time loss as possible. However, it cannot be avoided that speed will be reduced and travel time increased during the time of construction. The present study shows how intuitive judgments of travel time losses are biased in a way similar to the times saving bias (Svenson, 2008), but not perfectly corresponding to that bias. This means that when speed is decreased from a slow speed <50 km/h, the time loss is underestimated and when speed is decreased from a high speed >80 km/h it is overestimated. Also, drivers, politicians and policy makers who do not make exact calculations are likely victims of the time loss bias. The time loss bias was weakened but not eliminated by a debiasing instruction including mathematical computations of travel times. When driving speed restrictions are implemented, in particular on fast motorways, it is necessary to consider and counteract the time loss bias and inform the public. This can be done, for example, in communications about travel time facts, by information in driver training and by mounting temporary road signs informing about the average travel time prolongation due to a road work.     

Nonverbal communication during the learner lesson with a professional driving instructor: A novel investigation

BackgroundFundamental for the development of the driving and road use skills of the young driver is learning to drive through driving instruction and, in graduated driver licensing programs such as in Australia, driving supervision. In Queensland young drivers are required to log a minimum of 100 h supervised practice, with recent research revealing that parents provide most of this supervision. Queensland also offers young drivers a 10-h 3-for-1 bonus for professional driving instruction, such that one hour of professional instruction can be logged as three hours of practice, to a maximum of 30 logbook hours. Recent research efforts have begun to provide insight into the nature of the verbal instruction of both parents and professional instructors, and into the nonverbal communication between parents and learners. However nothing is known regarding the nonverbal communication between professional instructors and learners.MethodTen learner lessons (five male learners) with four professional instructors (four males) were captured via GoPro cameras. The nonverbal communication during the first, middle, and last 10 min of each lesson was coded as being posture and body orientation, gestures, facial expressions, proximity, humour, and eye contact, within the context of the accompanying verbal communication according to the value of (a) eager, or (b) cautious; the valence of (a) neutral, (b) positive, or (c) negative; and the purpose of (a) rapport, or (b) communication.ResultsOverall, posture and body orientation was the most common mechanism of nonverbal communication, while facial expressions and proximity were the least common mechanisms of nonverbal communication. In general the beginning, the middle, and the end of the lessons were characterised by a plethora of neutral, cautious interactions, and positive, eager interactions. However it is noteworthy that the rates at which learners and instructors engaged in these behaviours were found to change across the lesson. Specifically learners actively communication nonverbally through mechanisms such as eye contact, facial expressions and humour, while instructors appeared to manage building rapport and communicating safe vehicle and road use through nonverbal communication such as gestures, facial expressions and posture and body orientation, summarised in a model comprising a continuum of instruction.DiscussionWhile nonverbal communication is fundamental for effective verbal communication, and on occasion can replace verbal communication, and as such the professional – and the parental – driving lesson should optimise the use of nonverbal communication, at this time the optimal nature of nonverbal communication remains unknown. In addition, optimal verbal and nonverbal communication specifically suited to the driving context which involves a dynamic environment outside the vehicle, and at times a dynamic environment inside the vehicle, remains yet to be identified. The research findings provide unique insight into the nature of the nonverbal communication used by both learner drivers and professional driving instructors, in addition to the continuum of instruction model. As such, the findings provide a solid foundation for future research into, and guidance regarding, optimising the learner driving lesson.     

Using simulation to assess the ability of youth to safely operate tractors

BackgroundOperating farm tractors is dangerous for children. Recent studies document mismatches between children and physical requirements for operating tractors. The role of cognition has not been studied, because such research conducted in real-life situations places youth at risk. The objective of this study was to evaluate the feasibility and psychometric properties of a simulated virtual tractor environment to examine how children’s age and development impacts safe tractor operations.MethodsFifty-five male youth ages 10–17 living/working on farms with experience driving tractors tested the virtual environment and simulation modules. Six adult male farmers were recruited as a reference group to compare youth performance with adults.ResultsThe simulation had adequate face validity with realism scores reported between “somewhat” and “quite” realistic. Internal reliability of the simulation was excellent, as demonstrated by highly significant intraclass correlations for key indicators of performance (speeds and hazard clearances). While there was some evidence for construct validity, as indicated by trends in performance across the age groups, findings were mixed.ConclusionStudy findings support using simulation for assessing the abilities of children to safely operate tractors.     

Compensating for failed attention while driving

While operating a motor vehicle, drivers must pay attention to other moving vehicles and the roadside environment in order to detect and process critical information related to the driving task. Using a driving simulator, this study investigated the effects of an unexpected event on driver performance in environments of more or less clutter and under situations of high attentional load. Attentional load was manipulated by varying the number of neighboring vehicles participants tracked for lane changes. After baseline-driving behavior was established, the unexpected event occurred: a pedestrian ran into the driver’s path. Tracking-accuracy, brake initiation, swerving, and verbal report of the unexpected pedestrian were used to assess driver performance. All participants verbally reported noticing the pedestrian. However, analyses of driving behavior revealed differences in the reactions to the pedestrian: drivers braked faster and had significantly less deviation in their steering heading with a lower attentional load, and participants in low clutter environments had a larger overall change in velocity. This research advances the understanding of how drivers allocate attention between various stimuli and the trade-offs between a driver’s focus on an assigned task and external objects within the roadway environment. Moreover, the results of this research lend insight into how to construct roadway environments that encourage driver attention toward the most immediate and relevant information to reduce both vehicle-to-vehicle and vehicle-to-pedestrian interactions.