Subjective Workload Research Articles

Microsurgical training using an ex-vivo model: microscope vs 3D exoscope.

SUMMARYObjectiveThe aim of this study is to evaluate the feasibility of the 3D exoscope in a microvascular anastomosis training setting and compare it with the gold-standard technique using the operating microscope (OM).MethodsParticipants were recruited among otorhinolaryngology head and neck surgery (OHNS) residents of two tertiary care hospitals. Trainees were asked to complete 4 microvascular end-to-end anastomoses on chicken thighs with the OM and VITOM 3D exoscope. The performances were scored by experienced microvascular surgeons; an objective evaluation of the anastomosis and a subjective assessment of the workload were conducted.Results8 OHNS residents were recruited. Considering the amount of time needed to complete (TTC) the anastomosis, an improvement was shown by all the participants throughout the training program. The objective evaluation of the anastomosis did not show a significant difference. No significant differences were found by analyzing the subjective workload with the different tools.ConclusionsThis article represents the first attempt to compare the use of the OM and the 3D exoscope during training for microsurgery. The results of our study demonstrate the noninferiority of microsurgical training obtained using the 3D exoscope compared to that offered by the OM.

Did you even see that? visual sensory processing of single stimuli under different locomotor loads.

Modern living and working environments are more and more interspersed with the concurrent execution of locomotion and sensory processing, most often in the visual domain. Many job profiles involve the presentation of visual information while walking, for example in warehouse logistics work, where a worker has to manage walking to the correct aisle to pick up a package while being presented with visual information over data-glasses concerning the next order. Similar use-cases can be found in manufacturing jobs, for example in car montage assembly lines where next steps are presented via augmented reality headsets while walking at a slow pace. Considering the overall scarcity of cognitive resources available to be deployed to either the cognitive or motor processes, task performance decrements were found when increasing load in either domain. Interestingly, the walking motion also had beneficial effects on peripheral contrast detection and the inhibition of visual stream information. Taking these findings into account, we conducted a study that comprised the detection of single visual targets (Landolt Cs) within a broad range of the visual field (-40° to +40° visual angle) while either standing, walking, or walking with concurrent perturbations. We used questionnaire (NASA-TLX), behavioral (response times and accuracy), and neurophysiological data (ERPs and ERSPs) to quantify the effects of cognitive-motor interference. The study was conducted in a Gait Real-time Analysis Interactive Laboratory (GRAIL), using a 180° projection screen and a swayable and tiltable dual-belt treadmill. Questionnaire and behavioral measures showed common patterns. We found increasing subjective physical workload and behavioral decrements with increasing stimulus eccentricity and motor complexity. Electrophysiological results also indicated decrements in stimulus processing with higher stimulus eccentricity and movement complexity (P3, Theta), but highlighted a beneficial role when walking without perturbations and processing more peripheral stimuli regarding earlier sensory components (N1pc/N2pc, N2). These findings suggest that walking without impediments can enhance the visual processing of peripheral information and therefore help with perceiving non-foveal sensory content. Also, our results could help with re-evaluating previous findings in the context of cognitive-motor interference, as increased motor complexity might not always impede cognitive processing and performance.

0227 The effect of light on circadian entrainment for shifting from day to night flight operations

Abstract Introduction A midair collision during a routine nighttime air refueling training mission in the early morning hours of December 6, 2018, resulted in the tragic deaths of six Marine aircrew members and the loss of two US Marine Corps aircraft. Fatigue and the transition from day to night flights were called out as a problem area that continues to plague aviation commands. The goal of this study was to provide recommendations to the fleet regarding the limitations and best practices for shifting aviators from day to night operations to mitigate aviator fatigue and facilitate circadian re-alignment. Methods Longitudinal (10-day) within-subject assessment of aviators (N=9) in hybrid conditions. Aviators completed validated questionnaires for sleepiness and workload. Performance was assessed in simulated flight scenarios (one morning and three night sessions). The efficacy of a single 4-hour exposure of blue-enriched white light (~1000 lux) was assessed with the dim-light melatonin onset procedure. The study protocol attempted to replicate the work and rest patterns of aviators in the field who work during the day but could potentially be required to quickly shift their schedules to support night flight operations. Results The circadian phase of all participants was successfully delayed an average of 1.3 hours (range: 0.88-1.93 hours). Despite the lack of control over light exposure or other activities over the study period, participants reported less sleepiness and reduced subjective workload with improved flight performance. Conclusion Conclusions from the literature review and our study indicate that circadian entrainment in complex military operational settings should use light management as the dominant method for shifting the circadian clock. Based on these conclusions, we developed general recommendations and two circadian synchronization plans for aircrew switching from day to night operations. One plan shows a schedule that prepares for night operations by steadily shifting the daily schedule over multiple days. The other plan shows a schedule for aircrew who are required to shift from day to night operations abruptly without notice. Support (If Any) Supported by the Assistant Commandant of the Marine Corps.

Constructing Neural Network Model to Evaluate and Predict Human Error Probability in Nuclear Power Plants Based on Eye Response, Workload Rating, and Situation Awareness

The accurate assessment of human error probability (HEP) has an important impact on the safety of nuclear power plants. Therefore, it is necessary to develop a HEP model. This study analyzes the validity, sensitivity, and relationship between HEP and the indices of eye response and the subjective rating method. The analysis result showed that there is a correlation between HEP and the indices of eye response, subjective workload, and situation awareness level. Therefore, a back propagation neural network model was developed based on these indices. The correlation coefficient is more than 0.95 between the predicted data of the developed model and the target data. Also, the root mean square error was 0.0073, 0.0083, and 0.0077, and the determination coefficient was 0.965, 0.933, and 0.931 for the training, validation, and testing data sets, respectively. Therefore, the developed back propagation neural network model has reliable prediction accuracy for HEP.

Acute stress effects of impulsive noise during mental work

Impulsive sound has been found to annoy people more than steady-state sound or many other types of sound presented at the same sound level. This study examined the physiological, performance, and subjective effects of impulsive sound on working humans. Exposure to impulsive sound (65 dB LAeq) was compared with quiet sound (35 dB LAeq) and steady-state sound (65 dB LAeq). This parallel-group study, where each participant was exposed to one sound condition, had altogether 59 participants. Physiological stress was measured with stress hormone concentrations in plasma (cortisol and noradrenaline), heart rate variability (HRV), and blood pressure. Psychological stress was measured with subjective noise annoyance, workload, and fatigue. Performance was measured in tasks requiring constant concentration (visual and auditory serial recall and N-back). Compared to quiet sound, impulsive sound caused more annoyance, workload, and lack of energy, raised cortisol concentrations, reduced systolic blood pressure, and decreased accuracy in the 3-back task. Compared with steady-state sound, impulsive sound was experienced as more annoying and causing a higher workload and more lack of energy. Impulsive sound caused physiological and psychological stress and decreased performance compared to quiet sound. Part of this load was due to the increased sound level, which was evident as a physiological stress reaction. Still, there was also an extra stress effect related to the impulsiveness of the sound, reflected as a psychological experience. Special care should be paid to impulsive sound, especially in environments where people are performing mental work.

Domain- and task-analytic workload (DTAW) method: a methodology for predicting mental workload during severe accidents in nuclear power plants

Excessive mental workload reduces operators’ performance and threatens the safety of nuclear power plants (NPPs) in severe accident management (SAM). Given the lack of suitable mental workload measurement methods for SAM tasks, we proposed a Domain- and Task-Analytic Workload (DTAW) method to predict SAM workload. The DTAW method is developed in three stages: scenario construction based on work domain analysis, task analysis, and workload estimation with eight workload components scored through task-analytic and projective methods. To demonstrate its utility, we applied the method to construct two SAM scenarios and predict the mental workload demand of operators in these scenarios as compared to two design basis accident scenarios. With statistical analysis, the DTAW method can predict the overall subjective workload rated by NPP operators, be used to identify high-load tasks, cluster tasks with similar workload patterns, and provide direct implications for improving SAM strategies and supporting systems. Practitioner summary: To predict mental workload in severe accident management (SAM) scenarios in nuclear power plants, we proposed an analytic method and applied it to estimate mental workload in two SAM scenarios and two design basis accident (DBA) scenarios. We found that the workload pattern in SAM scenarios is different from that in DBA scenarios.

Augmented Reality Head-Up Display: A Visual Support During Malfunctions in Partially Automated Driving?

Malfunctions are a major challenge in partially automated driving. During such malfunctions, the driver must be able to adequately take over vehicle guidance without being requested to intervene. This may be particularly difficult in urban areas due to their high complexity and information density. Augmented Reality Head-Up Displays (ARHUDs) may have the potential to support the driver during the monitoring task by providing driving-related information at its required location in the primary field of view. The effects of an ARHUD compared to a Baseline concept in case of malfunctions were investigated in a driving simulation experiment with 52 participants. In a partially automated urban drive, participants experienced a longitudinal and a lateral malfunction in permuted order. The concepts–ARHUD or Baseline– were presented as a between-subject factor. The results showed significantly shorter take-over times when using the ARHUD, resulting in fewer crashes. For those who were able to avoid the crash, no differences in the take-over quality between both concepts were found. There was one difference in visual attention: the attention ratio on the instrument cluster was lower for the ARHUD. In addition, the ARHUD revealed a significantly higher trust and usability rating. However, there were no differences in acceptance and subjective workload between the two concepts. The results showed that the ARHUD has more potential to prevent crashes in the event of malfunctions compared to the Baseline. Nevertheless, the high number of crashes, regardless of the concept, showed the importance of a fallback level for partially automated urban driving.

The effects of dual-task interference on visual search and verbal memory

The operational costs of multitasking are more pressing given the increase in wearable technologies (head-up displays; HUDs) that facilitate multitasking. Often multitasking comes with performance costs, where the addition of more tasks impairs the performance of the tasks. The current study explored the extent to which multitasking interference can be characterised in simulated environments, as opposed to risky and harsh environments in real operational contexts. Forty-eight participants completed several trials where they performed a visual search task while navigating a simulated environment. There were three conditions: a standalone memory task, a standalone search task, and both tasks simultaneously. Results revealed significant dual-task interference when comparing the dual-task to each of the single-tasks. Results were corroborated by subjective workload and stress metrics. The results could prove useful for designing systems for individuals who routinely multitask in operational environments. Specifically, by furthering the understanding of their performance capabilities and trade-offs due to multitasking. Practitioner summary: Due to the demands of multitasking in operational environments, quantifying the degree of information lost on each task individually will aid in the understanding of the deficits of multitasking performance. This study shows that deficits in multi-tasking (via a HUD) can be understood in simulated environments to a similar degree as real-world tasks.

Gaming experience predicts UAS operator performance and workload in simulated search and rescue missions

Unmanned aircraft systems (UAS) operator training and selection procedures are still being refined to effectively address challenges related to performance, workload, and stress in UAS operation. Research suggests that experience with commercial videogames may test skills relevant to modern UAS operation. This study investigated the ability of videogame experience to predict operator performance, workload, and stress. Forty-nine participants performed 9 trials of a simulated search and rescue mission. It was expected that participants who more frequently played videogames would report lower levels of distress and workload, higher task engagement, and better overall performance. Results showed that gaming experience was negatively correlated with subjective workload and positively correlated with multiple measures of performance. Furthermore, nearly all observed gender-related differences were not present when gaming experience was controlled for. These results have implications for the role of gaming experience in remotely operated systems operator recruitment, selection, and training. Practitioner summary: This study examined how gaming experience influences UAS operator success in simulated search and rescue missions. Participants reported on their experience playing videogames before completing multiple experimental trials on a desktop computer. Results indicated that experience playing videogames significantly impacted performance, workload, and stress.

Evaluating mental workload during multitasking in simulated flight.

BackgroundPilots must process multiple streams of information simultaneously. Mental workload is one of the main issues in man–machine interactive mode when dealing with multiple tasks. This study aimed to combine functional near‐infrared spectroscopy (fNIRS) and electrocardiogram (ECG) to detect changes in mental workload during multitasking in a simulated flight.MethodsTwenty‐six participants performed three multitasking tasks at different mental workload levels. These mental workload levels were set by varying the number of subtasks. fNIRS and ECG signals were recorded during tasks. Participants filled in the national aeronautics and space administration task load index (NASA‐TLX) scale after each task. The effects of mental workload on scores of NASA‐TLX, performance of tasks, heart rate (HR), heart rate variability (HRV), and the prefrontal cortex (PFC) activation were analyzed.ResultsCompared to multitasking in lower mental workload conditions, participants exhibited higher scores of NASA‐TLX, HR, and PFC activation when multitasking in high mental workload conditions. Their performance was worse during the high mental workload multitasking condition, as evidenced by the higher average tracking distance, smaller number of response times, and longer response time of the meter. The standard deviation of the RR intervals (SDNN) was negatively correlated with subjective mental workload in the low task load condition and PFC activation was positively correlated with HR and subjective mental workload in the medium task load condition.ConclusionHR and PFC activation can be used to detect changes in mental workload during simulated flight multitasking tasks.

Telestration with augmented reality for visual presentation of intraoperative target structures in minimally invasive surgery: a randomized controlled study

AimsIn minimally invasive surgery (MIS), intraoperative guidance has been limited to verbal communication without direct visual guidance. Communication issues and mistaken instructions in training procedures can hinder correct identification of anatomical structures on the MIS screen. The iSurgeon system was developed to provide visual guidance in the operating room by telestration with augmented reality (AR).MethodsLaparoscopic novices (n = 60) were randomized in two groups in a cross-over design: group 1 trained only with verbal guidance first and then with additional telestration with AR on the operative screen and vice versa for group 2. Training consisted of laparoscopic basic training and subsequently a specifically designed training course, including a porcine laparoscopic cholecystectomy (LC). Outcome included time needed for training, performance with Global Operative Assessment of Laparoscopic Skills (GOALS), and Objective Structured Assessment of Technical Skills (OSATS) score for LC, complications, and subjective workload (NASA-TLX questionnaire).ResultsTelestration with AR led to significantly faster total training time (1163 ± 275 vs. 1658 ± 375 s, p < 0.001) and reduced error rates. LC on a porcine liver was performed significantly better (GOALS 21 ± 5 vs. 18 ± 4, p < 0.007 and OSATS 67 ± 11 vs. 61 ± 8, p < 0.015) and with less complications (13.3% vs. 40%, p < 0.020) with AR. Subjective workload and stress were significantly reduced during training with AR (33.6 ± 12.0 vs. 30.6 ± 12.9, p < 0.022).ConclusionTelestration with AR improves training success and safety in MIS. The next step will be the clinical application of telestration with AR and the development of a mobile version for remote guidance.

A new approach to manipulating aviator workload: A case for individualizing workload manipulations

The present study sought to manipulate workload individually for participants to evaluate whether individual manipulations of workload produces similar subjective ratings and performance changes across participants. Participants included eight Army-rated rotary-wing aviators who presented to the laboratory for two separate visits. During the first visit, individual responses to workload were determined, and during the second visit, individually manipulated high workload flights were completed. Outcome measures included flight performance and subjective workload ratings. Data were examined at the group and individual level. Subjective ratings of workload endorsed the individual workload manipulations, while performance data provided some additional support. By taking an individualized approach such as this, researchers and practitioners may be better able to control for individual differences influencing workload. This has important implications for system design and testing, development of new intervention technologies, and assessing methods for operator monitoring.

Evaluation of an Ecological Interface Design–Driven Augmentative and Alternative Communication Interface

This study evaluated the change in usability, mental workload and information transfer rate associated with an augmentative and alternative communication (AAC) interface designed through ecological interface design (EID). The design and development process is detailed in Shea et al. (2021) . Digital AAC interfaces are considered high-tech interventions for individuals who experience complex communication needs (e.g., from etiologies such as cerebral palsy) and enable users to select language options from a visual display. Interface usability, mental workload and information transfer rate collectively influence users’ communication. Ten AAC-naïve participants engaged in three semi–scripted conversations (verbal, AAC-mediated commercial interface, and EID interfaces) with an actor. Augmentative and alternative communication interfaces were accessed through a single switch pathway. Information transfer rate, error rate, heart rate variability and subjective workload performance measures were recorded for every trial. During AAC-mediated trials, interface interactions were also documented. The EID AAC interface presented improved communication in 5 out of 7 performance measures ( p &lt; .05). The EID AAC interface was associated with a significantly higher information transfer rate, lower error rate, less time elapsed between switch activations, less switch activation per word communicated and lower subjective workload. The application of EID to an AAC interface can lead to a significantly improved communication experience.

Point specification in collaborative visualization for 3D scalar fields using augmented reality

We compared three techniques to specify 3D positions for collaborative augmented reality (AR) visualization. AR head-mounted displays allow multiple users to share the same physical space, while keeping seamless social interactions. Interactions being key parts of exploratory visualization tasks, we adapted from the virtual reality literature three distinct techniques to specify points in 3D space, such as for placing annotations for which they cannot rely on existing data objects. We evaluated these techniques on their accuracy and speed, the user’s subjective workload and preferences, as well as their co-presence, mutual understanding, and behavior in collaborative tasks. Our results suggest that all the three techniques provide good mutual understanding and co-presence among collaborators. They differ, however, in the way users behave, their accuracy, and their speed.

The Impact of Visual and Cognitive Dual-Task Demands on Traffic Perception During Road Crossing of Older and Younger Pedestrians.

With the help of the current experiment, we wanted to learn more about the impact of visually demanding vs. cognitively demanding secondary tasks on the attention allocation of older pedestrians during the phase of traffic perception within the process of road crossing. For this purpose, we used two different road crossing tasks as well as two different secondary tasks. The road crossing “stop task” was a signal detection task, where an approaching car had to be detected. The road crossing “go task” was a dynamic visual search task, where the resolution of a busy road situation had to be identified. The visual secondary task was a static visual search task and the cognitive secondary task was a 1-back (memory) task. One younger group (≤ 30 years) and one older group (≥ 65 years) of participants completed the tasks as single vs. dual-tasks in all possible combinations. Performance was measured through errors and response time; in addition, the subjective workload was assessed via NASA-TLX. Analyses show that the visual secondary task reduces performance in the road crossing more strongly than the cognitive task, while the visual task itself is less impaired by the road crossing tasks than is the cognitive task. Overall, performance diminishes from single to dual-task completion. Results further indicate age effects in terms of increased errors and response time for older compared to younger participants. In addition to these age effects, age-specific dual-task effects emerge for response time in the go task along with the visual task as well as for response time in the cognitive task along with the go task. Subjective workload is higher in the dual-task conditions than in the single tasks. Findings are discussed with regard to theoretical and practical implications.

An Empirical and Subjective Model of Upper Extremity Fatigue Under Hypogravity.

In the context of extra-terrestrial missions, the effects of hypogravity (0 < G < 1) on the human body can reduce the well-being of the crew, cause musculoskeletal problems and affect their ability to perform tasks, especially during long-term missions. To date, studies of the effects of hypogravity on human movement are limited to experiments on the lower limbs. Here, we extend the knowledge base to the upper limbs, by conducting experiments to evaluate the effect of hypogravity on upper limb physical fatigue and mental workload in participants. Our hypothesis was that hypogravity would both increase participant productivity, by reducing overall physical fatigue expressed in Endurance Time, and reduce mental workload. Task Intensity-Endurance time curves are developed especially in seated positions, while performing static, dynamic, repetitive tasks. This experiment involved 32 healthy participants without chronic problems of the musculoskeletal system aged 33.59 ± 8.16 years. Using the collected data, fatigue models were constructed for tasks of varying Intensity. In addition, all participants completed the NASA – Task Load Index subjective mental workload assessment, which revealed the level of subjective workload when executing different tasks. We found two trends in the empirical fatigue models associated with the difference between the strength capabilities of males and females. The first is a significant positive (p = 0.002) relation between Endurance time and gravity level (⅙ G Moon, ⅓ G Mars, 1G) with negative coefficient for males and females for a static task. And there is marginal relation (p < 0.1) between overall mental workload and gravity level with a positive coefficient for males and females for the same task. The same trend was observed for dynamic and repetitive tasks. We concluded that the Task Intensity-Endurance Time model, adapted to hypogravity in combination with subjective mental assessment, is useful to human fatigue investigation. The combination of these methods used for ergonomic analysis and digital human modeling, could improve worker productivity. Finally, this study may help prepare astronauts for long-term missions on the Moon and Mars and improve our understanding of how we can prevent musculoskeletal disorders caused by hazardous manual handling under such extreme environments.

Supplemental Material for A cross-cultural study of the influence of environmental factors on VR gamers experience of spatial presence, enjoyment, and subjective workload: A preliminary study.

This study is a first step toward identifying some factors influencing spatial presence, enjoyment, and cognitive workload in virtual reality (VR) game play. The study was conducted in the Northeastern U.S. (n = 40) and Southwest Nigeria (n = 40) using a factorial experimental design with three environmental factors (i.e., lighting, flooring, and in-game sound) at two levels per factor. Participants were randomly assigned to one of eight experimental conditions, playing a VR American football game using Oculus Rift S on 3 separate days, under a different condition each time. Following VR game play, measures of spatial presence (α = .86), enjoyment (α = .89), and subjective workload (α = .78) were collected through self-report surveys. A factorial analysis of variance (ANOVA) was used to examine the influence of environmental factors on spatial presence, enjoyment, and subjective workload. The study found main effects of (a) lighting on subjective workload for the Nigerian sample (Day 2 and Day 3), (b) flooring on subjective workload for both cohorts (Day 2), and (c) in-game sound on spatial presence and subjective workload for the Nigerian sample (Day 3) and on spatial presence for the U.S. sample (Day 2 and Day 3). An interaction effect of lighting and flooring on subjective workload was found for the Nigerian sample on Day 1 and Day 2. An interaction effect of lighting, flooring, and in-game sound on enjoyment was found for the Nigerian sample on Day 3. We present implications for theory and practice.

A cross-cultural study of the influence of environmental factors on VR gamers experience of spatial presence, enjoyment, and subjective workload: A preliminary study.

This study is a first step toward identifying some factors influencing spatial presence, enjoyment, and cognitive workload in virtual reality (VR) game play. The study was conducted in the Northeastern U.S. (n = 40) and Southwest Nigeria (n = 40) using a factorial experimental design with three environmental factors (i.e., lighting, flooring, and in-game sound) at two levels per factor. Participants were randomly assigned to one of eight experimental conditions, playing a VR American football game using Oculus Rift S on 3 separate days, under a different condition each time. Following VR game play, measures of spatial presence (α = .86), enjoyment (α = .89), and subjective workload (α = .78) were collected through self-report surveys. A factorial analysis of variance (ANOVA) was used to examine the influence of environmental factors on spatial presence, enjoyment, and subjective workload. The study found main effects of (a) lighting on subjective workload for the Nigerian sample (Day 2 and Day 3), (b) flooring on subjective workload for both cohorts (Day 2), and (c) in-game sound on spatial presence and subjective workload for the Nigerian sample (Day 3) and on spatial presence for the U.S. sample (Day 2 and Day 3). An interaction effect of lighting and flooring on subjective workload was found for the Nigerian sample on Day 1 and Day 2. An interaction effect of lighting, flooring, and in-game sound on enjoyment was found for the Nigerian sample on Day 3. We present implications for theory and practice.

The challenges of entering the metaverse: An experiment on the effect of extended reality on workload

Information technologies exist to enable us to either do things we have not done before or do familiar things more efficiently. Metaverse (i.e. extended reality: XR) enables novel forms of engrossing telepresence, but it also may make mundate tasks more effortless. Such technologies increasingly facilitate our work, education, healthcare, consumption and entertainment; however, at the same time, metaverse bring a host of challenges. Therefore, we pose the question whether XR technologies, specifically Augmented Reality (AR) and Virtual Reality (VR), either increase or decrease the difficulties of carrying out everyday tasks. In the current study we conducted a 2 (AR: with vs. without) × 2 (VR: with vs. without) between-subject experiment where participants faced a shopping-related task (including navigating, movement, hand-interaction, information processing, information searching, storing, decision making, and simple calculation) to examine a proposed series of hypotheses. The NASA Task Load Index (NASA-TLX) was used to measure subjective workload when using an XR-mediated information system including six sub-dimensions of frustration, performance, effort, physical, mental, and temporal demand. The findings indicate that AR was significantly associated with overall workload, especially mental demand and effort, while VR had no significant effect on any workload sub-dimensions. There was a significant interaction effect between AR and VR on physical demand, effort, and overall workload. The results imply that the resources and cost of operating XR-mediated realities are different and higher than physical reality.

Analyzing the Influencing Factors and Workload Variation of Takeover Behavior in Semi-Autonomous Vehicles.

There are many factors that will influence the workload of drivers during autonomous driving. To examine the correlation between different factors and the workload of drivers, the influence of different factors on the workload variations is investigated from subjective and objective viewpoints. Thirty-seven drivers were recruited to participant the semi-autonomous driving experiments, and the drivers were required to complete different NDRTs (Non-Driving-Related Tasks): mistake finding, chatting, texting, and monitoring when the vehicle is in autonomous mode. Then, we introduced collision warning to signal there is risk ahead, and the warning signal was triggered at different TB (Time Budget)s before the risk, at which time the driver had to take over the driving task. During driving, the NASA-TLX-scale data were obtained to analyze the variation of the driver’s subjective workload. The driver’s pupil-diameter data acquired by the eye tracker from 100 s before the TOR (Take-Over Request) to 19 s after the takeover were obtained as well. The sliding time window was set to process the pupil-diameter data, and the 119-s normalized average pupil-diameter data under different NDRTs were fitted and modeled to analyze the variation of the driver’s objective workload. The results show that the total subjective workload score under the influence of different factors is as follows: obstacle-avoidance scene > lane-keeping scene; TB = 7 s and TB = 3 s have no significant difference; and mistake finding > chatting > texting > monitoring. The results of pupil-diameter data under different factors are as follows: obstacle-avoidance scene > lane-keeping scene; TB = 7 s > TB = 3 s; and monitoring type (chatting and monitoring) > texting type (mistake finding and texting). The research results can provide a reference for takeover safety prediction modeling based on workload.