Eye movements and hazard perception in active and passive driving

ABSTRACT

Differences in eye movement patterns are often found when comparing passive viewing paradigms to actively engaging in everyday tasks. Arguably, investigations into visuomotor control should therefore be most useful when conducted in settings that incorporate the intrinsic link between vision and action. We present a study that compares oculomotor behaviour and hazard reaction times across a simulated driving task and a comparable, but passive, video-based hazard perception task. We found that participants scanned the road less during the active driving task and fixated closer to the front of the vehicle. Participants were also slower to detect the hazards in the driving task. Our results suggest that the interactivity of simulated driving places increased demand upon the visual and attention systems than simply viewing driving movies. We offer insights into why these differences occur and explore the possible implications of such findings within the wider context of driver training and assessment.     

High perceptual load causes inattentional blindness and deafness in drivers

ABSTRACT

Perceptual load theory of attention predicts that the level of perceptual load in a primary task affects the processing of additional stimuli. Given the lack of ecologically valid evidence for the model, the current study assessed the effect of perceptual load on driver awareness during simulated driving tasks. The results showed that perceptual load dramatically affected driver awareness for visual and auditory stimuli, even those that were driving relevant and safety critical (e.g. pedestrians or the sound of a car horn). The results support load theory and suggest that perceptual load may be an important factor in driver safety.     

Adjustments to Local Friction in Multifinger Prehension

The authors studied the effects of surface friction at the digit-object interface on digit forces and moments when 12 participants statically held an object in a 5-digit grasp. The authors changed low-friction contact (LFC) with rayon and high-friction contact (HFC) with sandpaper independently for each digit in all 32 possible combinations. Normal forces of the thumb and virtual finger (VF), an imagined finger with a mechanical effect equal to that of the 4 fingers, increased with the thumb at LFC or with an increase in the number of fingers at LFC. When the thumb was at LFC, the thumb tangential force decreased. The VF tangential force decreased when the number of fingers at LFC increased. The interaction of the local responses to friction and the synergic responses necessary to maintain the equilibrium explain the coordination of individual digit forces.     

Spatial Compatibility Effects With Unimanual and Bimanual Wheel-Rotation Responses: An Homage to Guiard (1983)

ABSTRACT. Y. Guiard (1983) reported a prescient study of compatibility effects in response times for clockwise/counterclockwise wheel rotations to stimuli in left/right locations. Left-right coding of responses predominated in his study, but some results suggested that unimanual versus bimanual operation was also a factor. The authors report 3 experiments directly examining whether there is a difference in spatial compatibility effects obtained with wheel-rotation responses executed bimanually or unimanually (with left or right hand). Adopting a right-to-clockwise or left-to-counterclockwise mapping was advantageous for top, side, and bottom hand placements. This benefit interacted neither with unimanual or bimanual responding nor with the response hand. The results confirm that the critical relation is between the wheel and stimulus position, and is not effector dependent. This finding is in agreement with results from studies using discrete keypress responses, emphasizing that spatial coding of stimuli, actions, and their goals is of central importance in response-selection decisions.     

Assessing technology acceptance for skills development and real-world decision-making in the context of train driving

Advances in technology have improved operator performance and efficiency in transport but it is not uncommon for end users to resist technology in spite of its benefits. Operators may resist technology from genuine and legitimate concerns though it is often seen as unjustified. While beneficial, such resistance can have detrimental effects on operations and safety, and can result in the withdrawal of a technology. Theories relating to technology acceptance include elements such as perceptions about the purpose and use of the technology, personal impact, individual characteristics, peer influence, perceived equity, and organizational factors. Although considerable research into technology acceptance and resistance has been conducted in other domains, very little has been conducted in transportation. Findings from two Australian studies are reported which examined train driver attitudes to two state-of-the-art technologies aimed at enhancing skills development and real-world decision-making. The technologies were implemented in the form of in-vehicle information support and simulated learning. Analysis of interviews defined three overarching themes relating to technology resistance: task dynamics related to ways of working and safety; redundancy regarding the utility of the technology and the impact on job security; and personal impact with respect to effects on status and the drivers’ capacity to learn new skills. It is argued that domain-specific characteristics must be considered when designing and implementing new technologies to ensure that benefits of technologies are optimised. It is also argued that resistance should be seen as a positive element of the design and implementation process. This paper has high relevance for transport researchers, and practical application for rail organisations and policy makers.     

An examination of the relationships between cannabis use,driving under the influence of cannabis and risk-taking on the road

IntroductionSome studies have suggested that regular cannabis users appear to exhibit a general reckless driving style that may contribute to an inflated estimate of collisions related to driving under the influence of cannabis (DUIC) among this group.ObjectiveThis study investigated whether patterns of cannabis use would predict levels of self-reported unsafe driving behaviours and levels of performance observed in a driving simulator.MethodThe study investigated 48 young cannabis users with respect to frequency of cannabis consumption, alcohol use, driving exposure, self-reported dangerous driving habits, impulsivity, sensation seeking and performance in a driving simulator.ResultsCannabis use was positively associated with DUIC, with sensation seeking and with self-reports of risky driving. An ANOVA confirmed a significant effect of levels of consumption of cannabis among participants on self-report risk-taking in driving. Moreover, the observed behaviours during the simulation tasks correlated with risky driving habits, and with the self-reported frequency of driving in the hour following smoking cannabis or immediately after drinking alcohol.ConclusionSince cannabis usage and DUIC appear to be related to an overall reckless style of driving, it is proposed that public safety policies should be more holistic, simultaneously targeting multiple on-road dangerous behaviours for intervention.     

A cross-cultural analysis of aggressive driving: Evidence from Serbia and Romania

Using data from more than 700 drivers from Serbia and Romania, this study verified the dimensionality of aggressive driving in two countries from Eastern Europe. Specifically, the psychometric properties and invariance of the Romanian Driving Anger Expression Inventory (DAX; Deffenbacher et al., 2002, Sârbescu, 2012) were verified. Secondary aspects, such as differences in aggressive driving between countries or gender differences within countries, were also investigated. Our findings support the appropriateness of the three-factor structure in both countries, through the configural invariance of the DAX. Also, males report slightly higher levels of aggressive driving than women (small effect sizes), while Serbian drivers report higher levels of aggressive driving than Romanian drivers (strong effect sizes). Being the first research that verified the invariance of the DAX across two cultures, this study opens new paths and questions for research concerning aggressive driving.     

Investigating explanations in conditional and highly automated driving: The effects of situation awareness and modality

With the level of automation increases in vehicles, such as conditional and highly automated vehicles (AVs), drivers are becoming increasingly out of the control loop, especially in unexpected driving scenarios. Although it might be not necessary to require the drivers to intervene on most occasions, it is still important to improve drivers’ situation awareness (SA) in unexpected driving scenarios to improve their trust in and acceptance of AVs. In this study, we conceptualized SA at the levels of perception (SA L1), comprehension (SA L2), and projection (SA L3), and proposed an SA level-based explanation framework based on explainable AI. Then, we examined the effects of these explanations and their modalities on drivers’ situational trust, cognitive workload, as well as explanation satisfaction. A three (SA levels: SA L1, SA L2 and SA L3) by two (explanation modalities: visual, visual + audio) between-subjects experiment was conducted with 340 participants recruited from Amazon Mechanical Turk. The results indicated that by designing the explanations using the proposed SA-based framework, participants could redirect their attention to the important objects in the traffic and understand their meaning for the AV system. This improved their SA and filled the gap of understanding the correspondence of AV’s behavior in the particular situations which also increased their situational trust in AV. The results showed that participants reported the highest trust with SA L2 explanations, although the mental workload was assessed higher in this level. The results also provided insights into the relationship between the amount of information in explanations and modalities, showing that participants were more satisfied with visual-only explanations in the SA L1 and SA L2 conditions and were more satisfied with visual and auditory explanations in the SA L3 condition. Finally, we found that the cognitive workload was also higher in SA L2, possibly because the participants were actively interpreting the results, consistent with a higher level of situational trust. These findings demonstrated that properly designed explanations, based on our proposed SA-based framework, had significant implications for explaining AV behavior in conditional and highly automated driving.     

Perceived risk vs actual driving performance during distracted driving: A comparative analysis of phone use and other secondary distractions

The present study attempts to explore the association of drivers’ risk perception towards phone usage as well as other everyday distractions (operating a music player and eating during driving), and their driving performance observed during these distracted conditions. For this purpose, driving simulator experiments were conducted with 90 participants to collect their driving performance data and a questionnaire was conducted to obtain their basic details along with their risk perceptions. Firstly, the driving performance was divided into clusters using hierarchical clustering and the clustered subgroups were compared for crash and non-crash cases to identify the groups having significant performance degradation. Based on this comparison, the driving performance subgroups were then divided into the following crash risk probabilities: High risk, Moderate risk and Low risk. Further, the associations of perceived risk with these performance subgroups and other potential factors were analyzed using association rules mining technique. Most of the drivers (72.06%) reported texting as an extremely risky task. But, surprisingly none of them considered conversation as an extremely risky task. However, in case of conversation, it was found that even though the professional drivers reported the task to be not at all risky, the observed crash risk was high for them (S = 5.21%, C = 67.86%), indicating an underestimation of the associated risk by the drivers. Similarly, the results revealed that for music player and eating tasks, drivers reported the distracting tasks to be less risky, but, in some instances, their driving performance was associated with higher chances of crash occurrence. Many interesting associations of risk perception and driving performance with respect to demographic and driving characteristics were also obtained. The findings can be useful while designing the awareness programs related to distracted driving with an aim to reduce such practices.     

It’s about time! Earlier take-over requests in automated driving enable safer responses to conflicts

Automated driving (AD), which takes full responsibility for the driving task in certain conditions, is currently being developed. An important concern in AD is how to design a take-over request (TOR) that mitigates automation effects (e.g., delayed responses to conflict scenarios) that previous literature from simulator experiments has shown can occur. To address this concern, this study aims to investigate and compare driver responses to TORs and a lead-vehicle cut-out scenario under three conditions: (1) after a period of AD with a TOR issued early (18 s time-to-collision), (2) same as (1) except with a TOR issued late (9 s time-to-collision), and (3) baseline, with adaptive cruise control (ACC). This paper also compares the results to those of a previous study using the same conflict scenario but with near-perfect assisted driving system (SAE Level 2). The lead-vehicle cut-out scenario was encountered on a test track after 30 minutes driving with either ACC or AD. In AD the TOR was issued prior to the conflict object was revealed to the participants when the lead vehicle performed the cut-out (at conflict onset). This TOR strategy differed from previous driving-simulator studies that issued the TOR at conflict onset. The participants had to respond by steering and/or braking to avoid a crash. Our findings show that, independent of TOR timing, the drivers required similar amounts of time to 1) direct their first glance to the human–machine interface, 2) look forward, 3) end their secondary task, 4) put their hands on the steering wheel, and 5) deactivate automation. However, when the TOR was issued early rather than late, they started to brake earlier (even before conflict onset). All participants successfully managed to avoid crashing with the object, independent of the condition. AD with an early TOR resulted in the earliest response, while ACC drivers responded slightly earlier than the drivers in AD with the late TOR. Our findings do not support the findings of severe automation effects in previous driving-simulator studies. One reason for the difference is that when a TOR is issued prior to conflict onset, drivers are given the time needed for their preparatory actions (e.g., placing hands on the wheel, deactivating AD) that is not needed when driving with ACC or in manual driving (baseline), before having to respond to the conflict scenario. Thus, at conflict onset the drivers in AD are as ready to act (hands on wheel, eyes forward) as the drivers in the baseline and can perform an avoidance manoeuvre similar as to the baseline drive. Overall, the present study shows that AD does not need to end up in a highly critical situation if the TOR is issued early enough. In fact, AD with an early TOR may be safer than driving with ACC, because in the former drivers are more likely to brake earlier in preparation for the conflict. Finally, a TOR clearly communicates the need for drivers to resume manual control and handle potential events when AD has been deactivated. In our study, once the drivers had taken control, they clearly understood their responsibilities to respond to the conflict, in contrast to a previous study with a similar, near-perfect assisted driving system.