A Strategically Timed Verbal Task Improves Performance and Neurophysiological Alertness During Fatiguing Drives

This is the author's accepted manuscript. The original publication is available at http://hfs.sagepub.com/content/56/3/453.Objective: The objective of this study was to investigate if a verbal task can improve alertness and if performance changes are associated with changes in alertness as measured by EEG. Background: Previous research has shown that a secondary task can improve performance on a short, monotonous drive. The current work extends this by examining longer, fatiguing drives. The study also uses EEG to confirm that improved driving performance is concurrent with improved driver alertness. Method: A 90-min, monotonous simulator drive was used to place drivers in a fatigued state. Four secondary tasks were used: no verbal task, continuous verbal task, late verbal task, and a passive radio task. Results: When engaged in a secondary verbal task at the end of the drive, drivers showed improved lane-keeping performance and had improvements in neurophysiological measures of alertness. Conclusion: A strategically timed concurrent task can improve performance even for fatiguing drives. Application: Secondary-task countermeasures may prove useful for enhancing driving performance across a range of driving conditions

Exploring the effectiveness of a digital voice assistant to maintain driver alertness in partially automated vehicles

Objective: Vehicle automation shifts the driver's role from active operator to passive observer at the potential cost of degrading their alertness. This study investigated the role of an in-vehicle voice-based assistant (VA; conversing about traffic/road environment) to counter the disengaging and fatiguing effects of automation.Method: Twenty-four participants undertook two drives– with and without VA in a partially automated vehicle. Participants were subsequently categorized into high and low participation groups (based on their proportion of vocal exchanges with VA). The effectiveness of VA was assessed based on driver alertness measured using Karolinska Sleepiness Scale (KSS), eye-based sleepiness indicators and glance behavior, NASA-TLX workload rating and time to gain motor readiness in response to take-over request and performance rating made by the drivers.Results: Paired samples t-tests comparison of alertness measures across the two drives were conducted. Lower KSS rating, larger pupil diameter, higher glances (rear-mirror, roadside vehicles and signals in the drive with VA) and higher feedback ratings of VA indicated the efficiency of VA in improving driver alertness during automation. However, there was no significant difference in alertness or glance behavior between the driver groups (high and low-PR), although the time to resume steering control was significantly lower in the higher engagement group.Conclusion: The study successfully demonstrated the advantages of using a voice assistant (VA) to counter these effects of passive fatigue, for example, by reducing the time to gain motor-readiness following a TOR. The findings show that despite the low engagement in spoken conversation, active listening also positively influenced driver alertness and awareness during the drive in an automated vehicle

Exploring the benefits of conversing with a digital voice assistant during automated driving: A parametric duration model of takeover time

Vehicle automation allows drivers to disengage from driving causing a potential decline in their alertness. One of the major challenges of highly automated vehicles is to ensure a timely (with respect to safety and situation awareness) takeover in such conditions. For this purpose, the current study investigated the role of an in-vehicle digital voice-assistant (VA) in conditionally automated vehicles, offering spoken discourse relating specifically to contextual factors, such as the traffic situation and road environment. The study involved twenty-four participants, each taking two drives (counterbalanced): with VA and without VA, in a driving simulator. Participants were required to takeover vehicle control following the issuance of a takeover request (TOR) near the end of each drive. A parametric duration model was adopted to find the key factors determining takeover time (TOT). Paired comparisons showed higher alertness and higher active workload (mean NASA-TLX rating) during automation when accompanied by the VA. Paired t-test comparison of gaze behavior prior to takeover showed significantly higher instances of checking traffic signal, roadside objects, and the roadway during the drive with VA, indicating higher situation awareness. The parametric model indicated that the VA increased the likelihood of making a timely takeover by 39%. There was also some evidence suggesting that male drivers are likely to resume control 1.21 times earlier than female drivers. The study findings highlight the benefits of adopting a digital voice assistant to keep the drivers alert and aware about the recent traffic environment in partially automated vehicles

In-vehicle Drowsy Driving Detection and Alerting

DTNH2211D00237/0014Drowsy driving is a common phenomenon that increases the risk for fatal and injurious crashes. Technological innovations in the form of driver monitoring and notification systems may offer potential to reduce crashes due to drowsy driving. These systems monitor the driver\u2019s drowsy driving state and issue alerts when the driver is classified by the system as drowsy. Research shows that driver notification can be effective in improving performance over relatively short drives. However, the efficacy of such systems for improving performance and changing drowsy driver decision making over longer drives is unknown. The goal of this project was to evaluate the efficacy of two notifications, a lane departure warning (LDW) and a drowsiness notification with LDW (DN/LDW). The notification conditions were compared against a no-notification baseline during 4-hour overnight drives in a high-fidelity driving simulator with an incentive method designed to replicate the motivational tradeoffs common to drowsy driving, i.e., the desire to reach a destination versus one\u2019s own safety while driving drowsy. The combined DN/LDW, but not the LDW, was effective in reducing the frequency of lane departures and also in reducing the percentage of eyelid closure (PERCLOS) prior to lane departure events compared to baseline. There was no difference between the notification conditions and baseline with respect to the frequency or timing of breaks to rest, suggesting that although notifications improved driving performance, they did not alter decision making. These results suggest that notifications may aid drowsy drivers, but in-vehicle alerts may not be effective in changing the way drowsy drivers make decisions about whether and when to stop to rest

Driver fatigue and performance decrements over time-on-task: Effects and mitigation

Road crashes are a leading cause of death by injury globally (WHO, 2018), with fatigue estimated to contribute to 17% of fatal crashes (Tefft, 2012; TfNSW, 2017). A century of research has advanced our knowledge regarding the causes and effects of fatigue, but much remains unknown. In particular, while there is evidence that both heightened sleep-need and characteristics of the driving task can give rise to fatigue, the relative and combined effects of these factors are not sufficiently understood. Also, while several potential task-based fatigue interventions have been suggested, the effectiveness of these potential interventions is not well established. The present research is comprised of three empirical, driving simulator-based studies that aim to enhance our current understanding of the causes and possible mitigators of driver fatigue. The first study aimed to determine the contributions of time-on-task and sleep restriction, individually and combined, on the development of driver fatigue and performance impairment, and to investigate the potentially protective effects of a simple task modification. Sixty participants drove a simulated, monotonous route for 2 hours, under conditions of either prior sleep restriction or no sleep restriction, and with either normal speed limit signs or signs that required calculation of a mathematical problem, which has previously been shown to protect performance (Dunn & Williamson, 2012). Results clearly demonstrate that both sleep restriction and time-on-task contribute independently to driver fatigue, but there was some indication that sleep-restricted drivers could initially protect their performance, perhaps through the exertion of greater effort. The speed sign manipulation failed to show any protective effects. The second study was designed to further examine the effect of task-factors on driver state and performance over time-on-task. Exposure to a secondary cognitive task has been found to improve driving performance during the period of exposure, but the effects of this intervention over the duration of a drive has received limited attention. This study specifically investigated whether repeated exposures to a secondary task can overcome the degradation of performance and subjective state that occurs over time-on-task, whether any such benefits are dependent on the cognitive workload imposed by the task, and whether these beneficial effects might be attributable to increased effort. This study (N = 17, fully within participants design) employed a secondary cognitive task commonly found to elicit temporally limited beneficial effects in driving performance (n-back task), presenting it three times during an otherwise monotonous 90-minute simulated drive. Each participant performed three drives, one in each of three conditions, with order of condition counterbalanced between participants. The three conditions involved either three periods of 2-back (higher cognitive workload), three periods of 0-back (lower cognitive workload), or no n-back task (control). Results demonstrated that the 2-back condition marginally improved driving performance during exposure but neither condition reduced the degradation of performance or subjective state over time-on-task. The third study built upon study two by exploring whether increasing the frequency of secondary-task exposures would result in reduced performance decrements over time and also by comparing the effect of secondary-task exposure to the effect of taking breaks from driving, which is currently the typical advice provided to drivers to counteract fatigue and performance decrements. This study involved ninety-two participants driving a simulated, monotonous route for 90 minutes in one of six conditions: Driving only (control); infrequent 2-back exposure (three exposures, as per study 2); frequent 2-back exposure (five exposures); continuous 2-back exposure throughout the drive; infrequent breaks (three breaks); or frequent breaks (five breaks). Results indicate that infrequent exposure to a secondary task sustained driving performance over 90-minutes of time-on-task, which is inconsistent with the findings of study 2. Contrary to expectations, frequent secondary-task exposure was less beneficial than infrequent exposure, providing no benefit over the control condition. Continuous secondary-task exposure was detrimental to performance over time-on-task. The provision of breaks from driving also sustained driving performance over time-on-task, with more frequent breaks providing marginally greater benefit than less frequent breaks. Providing participants with breaks from driving was also beneficial for subjective states, measured as sleepiness, fatigue and effort. Results also confirmed that performance improvements in the secondary-task conditions were not solely a result of increased effort. These studies demonstrate that continuous time-on-task driving in highway-like conditions has a robust fatiguing effect. This effect is independent of, but exacerbated by, receiving insufficient sleep, highlighting the importance of taking continuous operating time into consideration, even in the context of seemingly simple tasks and when drivers are well-slept. Additionally, these studies demonstrate that repeated exposure to a secondary task might be an effective intervention for sustaining performance during monotonous drives of at least 90-minutes duration, but the nature and frequency of such interventions appear to be a key factor in their effectiveness. Results also suggest that performance might be best sustained by taking very frequent breaks, and although this might be impractical in the context of driving, this finding might be applied to a broad range of tasks that require sustained attention, including operations in security and quality control

Cognitive fatigue: Exploring the relationship between the fatigue effect and action video-game experience

the effects of cognitive fatigue. Despite this, there remain advantages to regularly playing action video games. In Study 1, VGPs were significantly better at multitasking on the MATB-II compared to the NVGPs. Further, VGPs also demonstrated superior multitasking when driving, as they made significantly fewer traffic violations compared to NVGPs when not fatigued. VGPs demonstrated eye-movements similar to those of expert drivers; however, this did not result in any difference in performance between the two groups. There was also some evidence of a positive effect of video game training, although there was no advantage of one training technique over the other. In Study 2, participants experienced the effects of cognitive fatigue to a lesser extent after video game training than compared to before training. Further, there was a significant improvement in multitasking performance after video game training, though as participants continued improving even at the three-month follow up test, it is unknown whether this was due to the video game training or due to practice effects on the MATB-II. Overall, despite improvements in sustained and divided attention performance from regular action video game playing or training, VGPs and trained-NVGPs are just as susceptible to the effects of cognitive fatigue as NVGPs