Exploring the Behaviour Change Wheel and the Theoretical Domains Framework in interventions for mobile phone driver distraction: A scoping review.

Mobile phone use while driving remains a significant traffic safety concern. Although numerous interventions have been developed to address it, there is a gap in the synthesis of relevant information through a comprehensive behaviour change lens. This scoping review uses the Behaviour Change Wheel (BCW) and the Theoretical Domains Framework (TDF) to examine the literature to (a) identify behavioural constructs targeted in interventions for mobile phone use while driving, (b) determine if the intervention success varied by sociodemographic group (e.g., age, gender, driving experience), and (c) map interventions to TDF domains to highlight areas for future research. Following the PRISMA extension for scoping reviews, we searched seven databases and identified 5,202 articles. After screening, 50 articles detailing 56 studies met the following inclusion criteria: (a) intervention studies, (b) providing details on methods and results, (c) written in English, and (d) targeting any driver behaviour related to mobile phone use while driving with a bottom-up approach, using not regulation or law enforcement, but individuals' psychological processes, such as cognitive, behavioural, and emotional. Findings show that most interventions targeted young drivers and were typically effective. Except for a few studies, the effectiveness of interventions targeting different sociodemographic groups either remained untested or revealed nonsignificant differences. This finding points to a gap in the literature, indicating a need for further investigation into the efficacy of interventions for different groups, and for tailoring and testing them accordingly. The interventions also often targeted multiple TDF domains, complicating the interpretation of the relative efficacy of specific domains. Most frequently targeted domains included beliefs and consequences, emotions, knowledge, social influence, social/professional role and identity, and behavioural regulation. Physical skills and optimism domains were not targeted in any intervention. Further, almost all interventions addressed deliberate engagement in mobile phone distractions, while the automatic and fast processes involved in such behaviours were often overlooked. Mobile phone distractions are in part habitual behaviours, yet the existing mitigation efforts mostly assumed intentional engagement. More focus on the habitual nature of mobile phone distractions is needed.

A Vehicle Simulation Study Examining the Effects of System Interface Design Elements on Performance in Different Vibration Environments Below 3 Hz.

OBJECTIVE: This study aimed to explore the relationship between system interface elements' design features and interaction performance in simulated vehicle vibration environments. BACKGROUND: Touch screens have been widely used in vehicle information systems, but few studies have focused on the decline of touchscreen interaction performance and task load increase when driving on unpaved roads. METHOD: The interaction performance (reaction time and task accuracy rate) with vibration frequencies below 3 Hz (1.5, 2.0, and 2.5 Hz) and different interface design elements was investigated employing a touch screen computer and E-prime software. RESULTS: The results indicate that vehicle vibration (below 3 Hz) can significantly reduce interaction performance with a vehicle information system interface. CONCLUSION: An appropriate increase in the physical size of the interface design features (visual stimulus materials and touch buttons) can help to mitigate this negative effect of vibration. APPLICATION: The results and findings of this study can be utilized for the design of information system interfaces as it relates to the vibration scenario of unpaved roads.

Preface to the Special Issue on Assessment and Effectiveness of Driver Monitoring Systems.

With vehicle automation becoming more commonplace, the role of the human driver is shifting from that of system operator to that of system supervisor. With this shift comes the risk of drivers becoming more disengaged from the task of supervising the system functioning, thus increasing the need for technology to keep drivers alert. This special issue includes the most up-to-date research on how drivers use vehicle automation, and the safety risks it may pose. It also investigates the accuracy that driver monitoring systems have in detecting conditions like driver distraction and drowsiness, and explores ways future drivers may respond to the broader introduction of this technology on passenger vehicles.

Drowsiness Mitigation Through Driver State Monitoring Systems: A Scoping Review.

OBJECTIVE: To explore the scope of available research and to identify research gaps on in-vehicle interventions for drowsiness that utilize driver monitoring systems (DMS). BACKGROUND: DMS are gaining popularity as a countermeasure against drowsiness. However, how these systems can be best utilized to guide driver attention is unclear. METHODS: A scoping review was conducted in adherence to PRISMA guidelines. Five electronic databases (ACM Digital Library, Scopus, IEEE Xplore, TRID, and SAE Mobilus) were systematically searched in April 2022. Original studies examining in-vehicle drowsiness interventions that use DMS in a driving context (e.g., driving simulator and driver interviews) passed the screening. Data on study details, state detection methods, and interventions were extracted. RESULTS: Twenty studies qualified for inclusion. Majority of interventions involved warnings (n = 16) with an auditory component (n = 14). Feedback displays (n = 4) and automation takeover (n = 4) were also investigated. Multistage interventions (n = 12) first cautioned the driver, then urged them to take an action, or initiated an automation takeover. Overall, interventions had a positive impact on sleepiness levels, driving performance, and user evaluations. Whether interventions effective for one type of sleepiness (e.g., passive vs. active fatigue) will perform well for another type is unclear. CONCLUSION: Literature mainly focused on developing sensors and improving the accuracy of DMS, but not on the driver interactions with these technologies. More intervention studies are needed in general and for investigating their long-term effects. APPLICATION: We list gaps and limitations in the DMS literature to guide researchers and practitioners in designing and evaluating effective safety systems for drowsy driving.

Targeting young driver emotions can reduce their cellphone distractions.

OBJECTIVE: This study sought to evaluate the relationship between young drivers' intention to engage in cellphone distractions while driving and their emotions towards the associated risks. First, we assessed whether the emotions of guilt, shame, and fear are associated with young drivers' intention to engage in cellphone distractions, through an extended Theory of Planned Behavior (TPB) model. Second, we evaluated whether road signs that may evoke these negative emotions reduce cellphone use intentions among young drivers. METHODS: An online survey was conducted with young drivers (18 to 25 years old) from Ontario, Canada. 403 responses were collected, of which, 99 responses were used to evaluate the first objective and all 403 responses were used to evaluate the second objective. RESULTS: Anticipating feelings of guilt, shame, and fear negatively predicted the intention to engage in cellphone distractions, above and beyond the standard TPB constructs (i.e., attitudes, subjective norms, and perceived behavioral control). When prompted with potentially emotion-evoking road signs (children crossing, my mom/dad works here), an increase in anticipated feelings of these emotions corresponded with lower intention to engage in cellphone distractions. CONCLUSION: Countermeasures that target young driver emotions toward distracted driving risks may be effective in reducing their distraction engagement. Future studies in more controlled environments can investigate causal relationships between emotions and distracted driving among young drivers.

Cell phone-related driver distraction: Habits predict behavior over and above the theory of planned behavior variables.

INTRODUCTION: Habits have often been overlooked in studies investigating cell phone-related driver distractions. This paper examines the association between habits and cell phone-related driver distractions within a mediation model based on the Theory of Planned Behavior (TPB). Additionally, it explores potential differences in behaviors across urban and rural driving environments and between males and females. METHOD: We conducted an online survey in China with 1,016 respondents, measuring attitudes, subjective norms, perceived behavioral control, self-reported behavior, and habits associated with cell phone use while driving. RESULTS: Data was analyzed using a two-stage structural equation modeling approach. Results indicate that the measurement model provided a good fit to the data and was invariant across urban and rural driving environments, as well as across genders. The latent path model investigating mediation also demonstrated a good fit and revealed that TPB variables (attitudes, subjective norms, and perceived behavioral control) partially mediated the relationship between cell phone-related habits and cell phone use while driving. The structural model was invariant across driving environments but not across genders, for which the extent of the differences were limited. Moreover, habits were strongly associated with subjective norms and perceived behavioral control, emerging as the strongest predictor of cell phone-related distractions. CONCLUSIONS: The findings suggest that habits should be considered in research on phone-related distracted driving behaviors and in the development of intervention designs.

Anticipatory Driving in Automated Vehicles: The Effects of Driving Experience and Distraction.

OBJECTIVE: To understand the influence of driving experience and distraction on drivers' anticipation of upcoming traffic events in automated vehicles. BACKGROUND: In nonautomated vehicles, experienced drivers spend more time looking at cues that indicate upcoming traffic events compared with novices, and distracted drivers spend less time looking at these cues compared with nondistracted drivers. Further, pre-event actions (i.e., proactive control actions prior to traffic events) are more prevalent among experienced drivers and nondistracted drivers. However, there is a research gap on the combined effects of experience and distraction on driver anticipation in automated vehicles. METHODS: A simulator experiment was conducted with 16 experienced and 16 novice drivers in a vehicle equipped with adaptive cruise control and lane-keeping assist systems (resulting in SAE Level 2 driving automation). Half of the participants in each experience group were provided with a self-paced primarily visual-manual secondary task. RESULTS: Drivers with the task spent less time looking at cues and were less likely to perform anticipatory driving behaviors (i.e., pre-event actions or preparation for pre-event actions such as hovering fingers over the automation disengage button). Experienced drivers exhibited more anticipatory driving behaviors, but their attention toward the cues was similar to novices for both task conditions. CONCLUSION: In line with nonautomated vehicle research, in automated vehicles, secondary task engagement impedes anticipation while driving experience facilitates anticipation. APPLICATION: Though Level 2 automation can relieve drivers of manually controlling the vehicle and allow engagement in distractions, visual-manual distraction engagement can impede anticipatory driving and should be restricted.

Factors Influencing Trust in Advanced Driver Assistance Systems for Current Users.

Understanding the factors influencing trust in advanced driver assistance systems (ADAS) may help inform training and education to support appropriate use. We surveyed 369 drivers with experience using both adaptive cruise control (ACC) and lane keeping assist (LKA). The survey included questions to assess trust in ADAS, along with objective knowledge about ADAS limitations, self-reported understanding of ADAS, familiarity with technology, propensity to trust technology, and demographics. Regression results showed that self-reported understanding, but not objective knowledge, predicted trust in ADAS. Self-reported understanding was not correlated with objective knowledge; overall, participants were not aware of many of the system limitations included in the survey. Propensity to trust technology was also a significant predictor of trust. Training/educational materials could be designed to inform drivers of potential gaps in their understanding and adjust expectations of ADAS to support appropriate trust for those with a high propensity to trust technology.

Drivers don't need to learn all ADAS limitations: A comparison of limitation-focused and responsibility-focused training approaches.

Expecting drivers to learn and remember numerous limitations may not be a practical approach to training for advanced driver assistance systems (ADAS), particularly for self-initiated training in the absence of formal training requirements. One alternative is focusing on the importance of the driver remaining engaged in the driving task (responsibility-focused approach). We investigated the effects of two training videos (responsibility-focused and limitation-focused) on reliance intention, trust, and ADAS knowledge. In a remote study, participants (N = 61) watched dashcam clips (8 that require takeover, 8 no takeover) and for each clip, they reported whether they would manually intervene and their trust in ADAS (assessing situational reliance intention and trust, respectively). Participants also completed a questionnaire that included items measuring ADAS knowledge. Responses were collected at three stages: pre-training, post-training, and a follow-up session (minimum four weeks later). There were no significant differences between approaches in terms of knowledge of situations in which ADAS would not work, appropriate situational reliance intention, or trust in takeover scenarios. Compared to the responsibility-focused video, the limitation-focused video was associated with lower trust in no takeover scenarios and negative bias at post-training (i.e., bias towards reporting that ADAS would not work for the knowledge questionnaire and bias towards taking manual control/not using ADAS for the dashcam clips). Given the limited differences between training approaches and potential drawbacks of the limitation-focused approach, our results suggest that the responsibility-focused training approach is worth exploring further.

Human factors applications in the design of decision support systems for population health: a scoping review.

INTRODUCTION: Public health professionals engage in complex cognitive tasks, often using evidence-based decision support tools to bolster their decision-making. Human factors methods take a user-centred approach to improve the design of systems, processes, and interfaces to better support planning and decision-making. While human factors methods have been applied to the design of clinical health tools, these methods are limited in the design of tools for population health. The objective of this scoping review is to develop a comprehensive understanding of how human factors techniques have been applied in the design of population health decision support tools. METHODS AND ANALYSIS: The scoping review will follow the methodology and framework proposed by Arksey and O'Malley. We include English-language documents between January 1990 and August 2021 describing the development, validation or application of human factors principles to decision support tools in population health. The search will include Ovid MEDLINE: Epub Ahead of Print, In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily and Ovid MEDLINE 1946-present; EMBASE, Scopus, PsycINFO, Compendex, IEEE Xplore and Inspec. The results will be integrated into Covidence. First, the abstract of all identified articles will be screened independently by two reviewers with disagreements being resolved by a third reviewer. Next, the full text for articles identified as include or inconclusive will be reviewed by two independent reviewers, leading to a final decision regarding inclusion. Reference lists of included articles will be manually screened to identify additional studies. Data will be extracted by one reviewer, verified by a second, and presented according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews. ETHICS AND DISSEMINATION: Ethics approval is not required for this work as human participants are not involved. The completed review will be published in a peer-reviewed, interdisciplinary journal.

The Influence of Visual-Manual Distractions on Anticipatory Driving.

OBJECTIVE: The aim of this study is to investigate how anticipatory driving is influenced by distraction. BACKGROUND: The anticipation of future events in traffic can allow potential gains in recognition and response times. Anticipatory actions (i.e., control actions in preparation for potential traffic changes) have been found to be more prevalent among experienced drivers in simulator studies when driving was the sole task. Despite the prevalence of visual-manual distractions and their negative effects on road safety, their influence on anticipatory driving has not yet been investigated beyond hazard anticipation. METHODS: A simulator experiment was conducted with 16 experienced and 16 novice drivers. Half of the participants were provided with a self-paced visual-manual secondary task presented on a dashboard display. RESULTS: More anticipatory actions were observed among experienced drivers; experienced drivers also exhibited more efficient visual scanning behaviors as indicated by higher glance rates toward and percent times looking at cues that facilitate the anticipation of upcoming events. Regardless of experience, those with the secondary task displayed reduced anticipatory actions and paid less attention toward anticipatory cues. However, experienced drivers had lower odds of exhibiting long glances toward the secondary task compared to novices. Further, the inclusion of glance duration on anticipatory cues increased the accuracy of a model predicting anticipatory actions based on on-road glance durations. CONCLUSION: The results provide additional evidence to existing literature supporting the role of driving experience and distraction engagement in anticipatory driving. APPLICATION: These findings can guide the design of in-vehicle systems and guide training programs to support anticipatory driving.

Hey, watch where you're going! An on-road study of driver scanning failures towards pedestrians and cyclists.

The safety of Vulnerable Road Users (VRUs), such as pedestrians and cyclists, is a serious public health concern, especially at urban intersections. A major reason for vehicle-VRU collisions is driver attentional errors. Prior studies suggest that cross-modal transportation experiences (e.g., being a driver who also cycles) improve visual attention allocation toward VRUs. However, these studies were conducted in simulators or in a laboratory, limiting their generalizability to real world driving. We utilized an instrumented vehicle equipped with eye tracking technology to examine (a) the prevalence of drivers' visual scanning failures toward VRUs at real intersections and (b) whether there is an effect of cycling experience on this prevalence. Twenty-six experienced drivers (13 cyclists and 13 non-cyclists), between the ages of 35 and 54, completed 18 different turns at urban Toronto intersections, for which gaze and video data were utilized to determine drivers' visual scanning failures towards areas where conflicting VRUs could approach. Among the 443 unique turn events, 25% were identified as having a visual scanning failure. Results from a mixed effects logit model showed that the odds of committing visual scanning failures towards VRUs during a turning maneuver at an intersection were 2.01 times greater for drivers without cycling experience compared to drivers with cycling experience. Given that our participants represented a low crash-risk age group, this study suggests that the rate at which VRUs are unattended to may be much higher.

Knowledge of and trust in advanced driver assistance systems.

Understanding what drivers know about state-of-the-art advanced driver assistance systems (ADAS), like adaptive cruise control (ACC) and lane keeping assistance (LKA) is important because such knowledge can influence trust in and reliance on the automation. We surveyed ADAS owners (N = 102) and non-owners (N = 262), with the primary objective of assessing knowledge and trust of ACC and LKA, and investigating the relationship between knowledge and trust among drivers who have not received special training. The survey contained demographic questions, ACC and LKA knowledge questionnaires (assessing knowledge of capabilities and limitations commonly found in owner's manuals), and ACC and LKA trust ratings. From the knowledge questionnaires, sensitivity (i.e., knowledge of the true capabilities of ACC and LKA) and response bias were assessed and used to predict trust. Results showed that owners did not have better knowledge of system capabilities/limitations than non-owners, in fact, owners had a stronger bias in favour of system capabilities. For non-owners, better knowledge of system capabilities was associated with lower trust, and those who were more biased towards endorsing system capabilities had higher trust. Neither knowledge nor response bias was associated with trust among owners. Further research is needed to confirm our results with a larger sample of owners, but given that it is also impractical to expect drivers to learn and remember all possible ADAS limitations, it may be beneficial to focus training efforts on improving drivers' overall understanding of the fallibility of ADAS and reinforcing their role when using ADAS to support appropriate trust and reliance.

Mitigating Teen Driver Distraction: In-Vehicle Feedback Based on Peer Social Norms.

OBJECTIVE: To investigate the efficacy of in-vehicle feedback based on peer social norms in mitigating teen driver distraction. BACKGROUND: Distraction is a significant problem among teen drivers. Research into the use of in-vehicle technologies to mitigate this issue has been limited. In particular, there is a need to study whether social norms interventions provided through in-vehicle feedback can be effective. Peers are important social referents for teens; thus, normative intervention based on this group is promising. Socially proximal referents have a greater influence on behavior; thus, tailoring peer norm feedback based on gender may provide additional benefits. METHOD: In this study, 57 teens completed a driving simulator experiment while performing a secondary task in three between-subject conditions: (a) postdrive feedback incorporating same-gender peer norms, (b) postdrive feedback incorporating opposite-gender peer norms, and (c) no feedback. Feedback involved information based on descriptive norms (what others do). RESULTS: Teens' self-reported frequency of distraction engagement was positively correlated with their perceptions of their peers' engagement in and approval of distractions. Feedback based on peer norms was effective in reducing distraction engagement and improving driving performance, with no difference between same- and opposite-gender feedback. CONCLUSION/APPLICATION: Feedback based on peer norms can help mitigate driver distraction among teens. Tailoring social norms feedback to teen gender appears to not provide any additional benefits. Longer-term effectiveness in real-world settings should be investigated.

In-vehicle displays to support driver anticipation of traffic conflicts in automated vehicles.

OBJECTIVE: This paper investigates the effectiveness of in-vehicle displays in supporting drivers' anticipation of traffic conflicts in automated vehicles (AVs). BACKGROUND: Providing takeover requests (TORs) along with information on automation capability (AC) has been found effective in supporting AV drivers' reactions to traffic conflicts. However, it is unclear what type of information can support drivers in anticipating traffic conflicts, so they can intervene (pre-event action) or prepare to intervene (pre-event preparation) proactively to avert them. METHOD: In a driving simulator study with 24 experienced and 24 novice drivers, we evaluated the effectiveness of two in-vehicle displays in supporting anticipatory driving in AVs with adaptive cruise control and lane keeping assistance: TORAC (TOR + AC information) and STTORAC displays (surrounding traffic (ST) information + TOR + AC information). Both displays were evaluated against a baseline display that only showed whether the automation was engaged. RESULTS: Compared to the baseline display, STTORAC led to more anticipatory driving behaviors (pre-event action or pre-event preparation) while TORAC led to less, along with decreased attention to environmental cues that indicated an upcoming event. STTORAC led to the highest level of driving safety, as indicated by minimum gap time for scenarios that required driver intervention, followed by TORAC, and then the baseline display. CONCLUSIONS: Providing surrounding traffic information to drivers of AVs, in addition to TORs and automation capability information, can support their anticipation of potential traffic conflicts. Without the surrounding traffic information, drivers can over-rely on displays that provide TORs and automation capability information.

The effect of intraoperative distractions on severe technical events in laparoscopic bariatric surgery.

BACKGROUND: Given the complexity of the operating room (OR), it is unsurprising that surgeons frequently feel distracted while performing operative tasks. However, this relationship is not well studied in live surgeries. The objective of this study is to investigate the relationship between intraoperative distractions and technical events using surgical data. METHODS: Roux-en-Y gastric bypass operation data from three tertiary care hospitals in Toronto, Canada were collected prospectively between 2017 and 2019 by a comprehensive operative capture platform (OR Black Box) and analyzed retrospectively. Time-synchronized audiovisual recordings of the OR and laparoscopic videos of the operation were collected, along with clinical data from the electronic health record. Video data was labeled for technical data, non-technical data, and distractions by trained coders. Procedural steps were categorized based on criticality. The relationship between severe technical events (case having 0 or 1 events vs. 2 or more) and the rate of distractions (machine alarms, external communications, people entering/exiting) in critical procedural steps was assessed through logistic regression, adjusting for team factors (surgeons' technical skills, nurse changeovers). RESULTS: 60 Roux-en-Y cases were analyzed. Average case duration was 83.2 min (SD = 21.97). Distractions occurred 47.6 times/h (SD = 20.3), with most frequent distraction being machine alarms (4.45/10 min, SD = 2.88). For unadjusted analysis, alarms (OR = 1.29, 95% CI 1.05-1.66) and surgeon's technical skills (OR = 0.65, 95% CI 0.43-0.93) were found to be correlated with severe technical events. After adjusting for team factors, alarms were found to be positively related with the presence of severe technical events (OR = 1.58, 95% CI 1.18-2.33) during high-criticality procedural steps. CONCLUSIONS: This study showed a significant association between intraoperative distractions, in particular machine alarms, and severe technical events during high-criticality procedural steps. Further investigation will assess the temporal relationship between distractions and technical events and assess mitigation strategies to create a safer surgical environment.

Searching for Street Parking: Effects on Driver Vehicle Control, Workload, Physiology, and Glances.

Urban areas that allow street parking exhibit a heightened crash risk that is often attributed to factors such as reduced road width, decreased visibility, and interruptions to traffic flow. No previous on-road studies have investigated how the demands of searching for parking affect driving performance, physiology, and visual attention allocation. We are interested in these effects on the driver and their possible influence on the safety of the environment. While simulator studies offer several benefits, the physical, mental and social pressures incurred by searching for parking in an urban streetscape cannot be emulated in a simulator. We conducted an on-road instrumented vehicle study with 28 participants driving in downtown Toronto, Canada to explore the effect of searching for street parking on drivers. During the experiment, participants drove two routes in a counterbalanced order: one route with a parking search task, and the other route as a baseline. Speed and lane position were measured via vehicle instrumentation, heart rate and galvanic skin response were measured through physiological sensors, and gaze position was collected through a head-mounted eye-tracker. Participants completed the NASA Task Load Index after each route. It was found that while searching for parking, participants drove slower and closer to the curb, and perceived higher workload. While there were no statistically significant effects in physiological measures, there was a rise in heart rate approaching statistical significance. A detailed analysis of eye-tracking data revealed a clear change in glance behavior while searching for parking, with an increase in long off-road glances (>2 s) and decrease in shorter off-road glances (<1.6 s). Some exhibited behaviors (e.g., slowing down) may be seen to compensate for the potentially negative effects of increased demands associated with parking search, while others (e.g., increase in long off-road glances) have the potential to increase crash risk. This study acts as an important first step in revealing changes in driving performance, physiology and glance behavior brought on by searching for parking in a real-world urban environment.

Eye glances towards conflict-relevant cues: the roles of anticipatory competence and driver experience.

OBJECTIVE: This paper analyzes the effects of anticipatory competence and driver experience on glance patterns towards visual cues that indicate conflict situations. BACKGROUND: Prior research has shown that experienced drivers' visual scanning patterns differ from those of novices. Experienced drivers are less erratic and more systematic in their monitoring of the environment. We have also shown in an earlier study that driving experience improves anticipatory competence in that it leads to a higher number of timely proactive actions in conflict-scenarios (avoidance actions prior to, as opposed to in reaction to a conflict). This paper investigates glance patterns specifically to relevant visual cues in conflict scenarios to determine whether glance patterns of anticipatory drivers who exhibit proactive actions differ from those who do not. It also investigates whether experienced drivers pay more attention to these cues compared to novices. METHOD: We conducted a simulator experiment with 24 experienced and 24 novice drivers. As part of the experiment, all drivers completed three distinct traffic scenarios, each with a conflict situation. RESULTS: The results show that drivers who exhibited proactive actions had more frequent and longer glances towards conflict-relevant cues than those who did not exhibit any. Similarly, experienced drivers focused on these visual cues more often, and for longer durations compared to novices. Further, experienced drivers who exhibited proactive actions looked at the cues more often compared to experienced drivers who did not exhibit any; there was no significant difference for novice drivers. CONCLUSION: These findings speak to the role of situation-specific visual cues for anticipatory competence, and to the importance of driver experience to aid in the interpretation of these cues. Future research should seek to confirm our findings in a wider variety of driving scenarios.

The effect of cognitive distraction on perception-response time to unexpected abrupt and gradually onset roadway hazards.

OBJECTIVE: A driving simulator study was conducted to investigate the effect of cognitive distraction on different stages of perception-response time (saccade latency, processing time, and movement time) to unexpected roadway hazards, both when the hazard onset is abrupt and when it is gradual. BACKGROUND: Prior studies, which typically focus on overall response times, have demonstrated that distraction, including cognitive distraction, leads to an increase in response times. Studies have also shown that response times differ depending on the type and location of the hazard. However, there is limited research into the effect of cognitive distraction for gradually developing hazards (e.g., a left-turn across path vehicle), as existing research primarily focuses on abrupt hazard onsets (e.g., lead vehicle braking). METHOD: Twenty-four participants were presented with three different emergency roadway hazards, including one abrupt onset hazard (a pedestrian stepping onto the roadway from in front of a parked vehicle) and two gradually developing hazards (an oncoming vehicle turning left across the driver's path and a vehicle accelerating perpendicularly into the driver's path from the right). Half of the participants completed a delayed digit recall task (cognitive distraction condition), the other half did not (control condition). RESULTS: The left-turn across path hazard was particularly characterized by the long processing period (initiation of the saccade towards the hazard to initial motor response), whereas the pedestrian hazard was more notable for the shortest saccadic latency (hazard onset to the start of the saccade towards the hazard). Cognitive distraction led to a significant increase in brake reaction time for the right-incursion vehicle hazard, in processing time for the left-turn across path hazard, and a marginally significant increase in saccadic latency for the pedestrian and right-incursion vehicle hazards. CONCLUSION: Hazard ambiguity due to gradual onset, such as with the left-turn across path hazard, appears to increase the processing duration before a response is executed, especially when distracted. Abrupt hazard onset appears to induce shorter saccadic latencies than gradual onsets likely due to a stronger attentional capture property. However, cognitive distraction may increase saccadic latencies for these types of hazards.

Voluntary- and Involuntary-Distraction Engagement: An Exploratory Study of Individual Differences.

Objective The aim of this study was to explore individual differences in voluntary and involuntary driver-distraction engagement. Background Distractions may stem from intentional engagement in secondary tasks (voluntary) or failing to suppress non-driving-related stimuli or information (involuntary). A wealth of literature has examined voluntary distraction; involuntary distraction is not particularly well understood. Individual factors, such as age, are known to play a role in how drivers engage in distractions. However, it is unclear which individual factors are associated with voluntary- versus involuntary-distraction engagement and whether there is a relation between how drivers engage in these two distraction types. Method Thirty-six participants, ages 25 to 39, drove in a simulator under three conditions: voluntary distraction with a self-paced visual-manual task on a secondary display, involuntary distraction with abrupt onset of irrelevant visual-audio stimuli on the secondary display, and no distraction. Results The number of glances toward the secondary display under voluntary distraction was not correlated to that under involuntary distraction. The former was associated with gender, age, annual mileage, and self-reported distraction engagement; such associations were not observed for the latter. Accelerator release time in response to lead-vehicle braking was delayed similarly under both conditions. Conclusion Propensity to engage in voluntary distractions appears to be not related to the inability of suppressing involuntary distractions. Further, voluntary and involuntary distraction both affect braking response. These findings have implications for design of in-vehicle technologies, which may be sources of both distraction types.