The effect of human-machine interface modality, specificity, and timing on driver performance and behavior while using vehicle automation.

The effectiveness of the human-machine interface (HMI) in a driving automation system during takeover situations is based, in part, on its design. Past research has indicated that modality, specificity, and timing of the HMI have an impact on driver behavior. The objective of this study was to examine the effectiveness of two HMIs, which vary by modality, specificity, and timing, on drivers' takeover time, performance, and eye glance behavior. Drivers' behavior was examined in a driving simulator study with different levels of automation, varying traffic conditions, and while completing a non-driving related task. Results indicated that HMI type had a statistically significant effect on velocity and off-road eye glances such that those who were exposed to an HMI that gave multimodal warnings with greater specificity exhibited better performance. There were no effects of HMI on acceleration, lane position, or other eye glance metrics (e.g., on road glance duration). Future work should disentangle HMI design further to determine exactly which aspects of design yield between safety critical behavior.

A simulator study assessing the effectiveness of training and warning systems on drivers' response performance to vehicle cyberattacks.

Modern vehicles are vulnerable to cyberattacks and the consequences can be severe. While technological efforts have attempted to address the problem, the role of human drivers is understudied. This study aims to assess the effectiveness of training and warning systems on drivers' response behavior to vehicle cyberattacks. Thirty-two participants completed a driving simulator study to assess the effectiveness of training and warning system according to their velocity, deceleration events, and count of cautionary behaviors. Participants, who held a valid United States driving license and had a mean age of 20.4 years old, were equally assigned to one of four groups: control (n = 8), training-only (n = 8), warning-only (n = 8), training and warning groups (n = 8). For each drive, mixed ANOVAs were implemented on the velocity variables and Poisson regression was conducted on the normalized time with large deceleration events and cautionary behavior variables. Overall, the results suggest that drivers' response behaviors were moderately affected by the training programs and the warning messages. Most drivers who received training or warning messages responded safely and appropriately to cyberattacks, e.g., by slowing down, pulling over, or performing cautionary behaviors, but only in specific cyberattack events. Training programs show promise in improving drivers' responses toward vehicle cyberattacks, and warning messages show rather moderate improvement but can be further refined to yield consistent behavior.

Evaluation of a 3M (mistakes, mentoring, and mastery) training program for transfer of control situations in a level 2 automated driving system.

Drivers must actively supervise automation as it can only function in limited conditions. A failure to supervise the system has negative consequences in terms of missed requests to take over control and may cause crashes or jeopardize safety. The objective of this study is to determine the effect of a novel, 3M (Mistakes, Mentoring, and Mastery) training program on drivers' behavior while using level 2 driving automation systems. To achieve this, 36 participants were assigned randomly to three different training programs (3M training, User manual, and Placebo) and drove through scenarios on a fixed-based driving simulator. The results showed that drivers in the 3M training group took back control more effectively when the driving automation system reached its limits compared to drivers who received User manual or Placebo training. Drivers in the 3M training Group also had higher situation awareness and improved trust in automation. The results indicate that an interactive approach to training with regards to vehicle automation can help drivers more safely interact with automation systems.

Frequency and Quality of Exposure to Adaptive Cruise Control and Impact on Trust, Workload, and Mental Models.

Advanced Driver Assistance Systems (ADAS) support drivers with some driving tasks. However, drivers may lack appropriate knowledge about ADAS resulting in inadequate mental models. This may result in drivers misusing ADAS, or mistrusting the technologies, especially after encountering edge-case events (situations beyond the capability of an ADAS where the system may malfunction or fail) and may also adversely affect driver workload. Literature suggests mental models could be improved through exposure to ADAS-related driving situations, especially those related to ADAS capabilities and limitations. The objective of this study was to examine the impact of frequency and quality of exposure on drivers' understanding of Adaptive Cruise Control (ACC), their trust, and their workload after driving with ACC. Sixteen novice ACC users were recruited for this longitudinal driving simulator study. Drivers were randomly assigned to one of two groups - the 'Regular Exposure' group encountering 'routine' edge-case events, and the 'Enhanced Exposure' group encountering 'routine' and 'rare' events. Each participant undertook four different simulator sessions, each separated by about a week. Each session comprised a simulator drive featuring five edge-case scenarios. The study followed a mixed-subject design, with exposure frequency as the within-subject variable, and quality of exposure (defined by two groups) as the between-subject variable. Surveys measured drivers' trust, workload, and mental models. The results from the analyses using linear regression models revealed that drivers' mental models about ACC improve with frequency of exposure to ACC and associated edge-case driving situations. This was more the case for drivers who experienced 'rare' ACC edge cases. The findings also indicate that for those who encountered 'rare' edge cases, workload was higher and trust was lower than those who did not. These findings are significant since they underline the importance of experience and familiarity with ADAS for safe operation. While these findings indicate that drivers benefit from increased exposure to ACC and edge cases in terms of appropriate use of ADAS, and ultimately promise crash reductions and injury prevention, a challenge remains regarding how to provide drivers with appropriate exposure in a safe manner.

Factors affecting drivers' off-road glance behavior while interacting with in-vehicle voice interfaces.

In-vehicle voice-based interfaces have been massively embedded in modern vehicles as a countermeasure to visual-manual distractions. However, limited data are available regarding the actual visual demands imposed on the driver when interacting with such an interface. How those factors that are associated with the drivers themselves affect their visual behavior when interacting with an in-vehicle voice-based interface remains understudied. This study focused on investigating factors affecting drivers' off-road visual behavior while interacting with a voice-based interface. A secondary data analysis leveraging structural equation modeling was performed based on data collected from a large-scale field experiment wherein participants drove a vehicle on the highway and performed a series of tasks using an in-vehicle voice interface. The results indicate that while voice-based interfaces are designed to help reduce drivers' visual demands, drivers can still direct their eyes off the road for a prolonged period of time during the interaction and exhibit potentially risky visual behavior. In addition, individual-level factors can exert influence on drivers' off-road visual behavior in such a way that older drivers and drivers with higher trust in technologies are associated with more long eyes-off-road glances when interacting with a voice-based interface. To promote the general public's adoption of in-vehicle voice interfaces and support safe interactions, we recommend relevant research and system design consider drivers' trust in, perceptions, and previous usage of similar technologies, as well as their individual characteristics such as age.

Looking out or Looking Away?-Exploring the Impact of Driving With a Passenger on Young Drivers' Eye Glance Behavior.

OBJECTIVE: To explore how passenger presence and the degree of association between young driver and passenger influences young drivers' eye glance behavior when they are subjected to distraction. BACKGROUND: Young drivers (18-20 years old) are at an elevated crash risk when subjected to distraction. They are likely to be distracted even further when they drive with passengers. However, the eye glance behavior of these drivers when driving with passengers has not been explored. METHOD: Eye glance data of 34 young drivers between the ages of 18 and 20 years were collected. Participants drove with and without a passenger while subjected to three distracting tasks (visual-manual, cognitive, or visual-cognitive) and driving scenarios that required driver attention. RESULTS: Visual-cognitive as well as visual-manual states of distraction result in higher mean and standard deviation of glance duration, along with higher number of glances away from road. Passenger presence is found to negatively influence young drivers' eye glance behavior. The degree of association between the young driver and the passenger may help reduce the deviation of eye glances towards the task-related objects. CONCLUSION: In addition to distraction, passengers have a negative influence on the eye glance behavior of young drivers. However, a high degree of association between driver and passenger may mitigate the negative impact of distraction on the eye glance behavior of young drivers. APPLICATION (NON-THEORETICAL WORKS): This research may aid in the design of interventions that improve young drivers' eye glance behavior when they drive with their peers.

The effect of hazard awareness training on teen drivers of varying socioeconomic status.

OBJECTIVE: To compare the effectiveness of the Risk Awareness and Perception Training (RAPT) program among teens of various socioeconomic status (SES). METHODS: A secondary analysis was undertaken of data collected from 5036 teen participants for a study in 2011. They were randomly assigned to either receive RAPT or a placebo training. The total number of crashes (property damage only and injury) within the first 12 months after licensure was recorded. A Poisson regression model was employed to investigate the effectiveness of RAPT in terms of crash frequency among teens in different levels of SES, as measured by SES level (high or low) or poverty rate. RESULTS: Poverty rate was significantly associated with participants' crash frequency within the first 12 months after licensure such that when poverty rate increased, the crash frequency increased. The interacting effect of poverty rate and training was also significant. When compared to participants who did not receive RAPT, participants who received RAPT had fewer crashes when poverty rate increased. CONCLUSION: The RAPT program attenuated the negative effect of teen drivers' SES on crashes. No significant effect of sex or age was found, indicating that in terms of crashes, regardless of age or sex, RAPT is equally effective at reducing crashes for lower SES teens.

Impact of L2 automated systems on hazard anticipation and mitigation behavior of young drivers with varying levels of Attention Deficit Hyperactivity Disorder symptomatology.

Level 2 (L2) driving automation systems that maintain latitudinal and longitudinal control of the vehicle decrease mental workload and result in drivers failing to monitor and respond to potential roadway hazards. This issue is potentially important for young drivers with symptoms of Attention Deficit Hyperactivity Disorder (ADHD) since they have known difficulties anticipating and mitigating potential hazards on the road, a skill which requires attention. The objective of this study is to investigate how the use of partially automated (L2) systems and manual systems impacts hazard anticipation and mitigation among young drivers with varying levels of ADHD symptomatology. Sixty-eight drivers, classified into two groups - high and low ADHD symptomatology-navigated twice through three scenarios on a driving simulator, once with an L2 and once with a manual system. The results indicated that: (i) the hazard anticipation skills of drivers with both high and low ADHD symptomatology were depressed in the L2 condition relative to the manual condition; (ii) the hazard mitigations skills of drivers with both high and low ADHD symptomatology were depressed in the L2 condition relative to the manual condition on two measures, but improved on a third measure; and (iii) the hazard anticipation and mitigation skills of drivers with high and low ADHD symptomatology were differentially impacted, both within and across the two levels of automation. Taken together, the results indicate the pernicious and often hard to predict consequences of higher levels of automation for different populations of younger drivers.

Driving distracted with friends: Effect of passengers and driver distraction on young drivers' behavior.

Both passengers and driver distraction can have negative effects on young driver behavior. However, it is not known how these two concepts interact to influence driver behavior. The objective of this study was to examine the effect of passenger presence and driver distraction on young drivers' behavior. Forty-eight participants aged 18-20 participated in a driving simulator study. Participants completed three distracting tasks (visual, cognitive, or combined) while navigating a highway scenario. Results indicated that passenger presence interacted with driver distraction to have an effect on elevated g-force events in curves. Separately, distraction affected driving performance differently according to whether the task was visual, cognitive or combined. Having a close friendship resulted in less speeding and male drivers tended to maintain a better lane position compared to females. The results have implications for licensing laws as well as intervention programs aimed at improving young driver behavior.

Does order matter? Investigating the effect of sequence on glance duration during on-road driving.

Previous literature has shown that vehicle crash risks increases as drivers' off-road glance duration increases. Many factors influence drivers' glance duration such as individual differences, driving environment, or task characteristics. Theories and past studies suggest that glance duration increases as the task progresses, but the exact relationship between glance sequence and glance durations is not fully understood. The purpose of this study was to examine the effect of glance sequence on glance duration among drivers completing a visual-manual radio tuning task and an auditory-vocal based multi-modal navigation entry task. Eighty participants drove a vehicle on urban highways while completing radio tuning and navigation entry tasks. Forty participants drove under an experimental protocol that required three button presses followed by rotation of a tuning knob to complete the radio tuning task while the other forty participants completed the task with one less button press. Multiple statistical analyses were conducted to measure the effect of glance sequence on glance duration. Results showed that across both tasks and a variety of statistical tests, glance sequence had inconsistent effects on glance duration-the effects varied according to the number of glances, task type, and data set that was being evaluated. Results suggest that other aspects of the task as well as interface design effect glance duration and should be considered in the context of examining driver attention or lack thereof. All in all, interface design and task characteristics have a more influential impact on glance duration than glance sequence, suggesting that classical design considerations impacting driver attention, such as the size and location of buttons, remain fundamental in designing in-vehicle interfaces.

Measurement of driver calibration and the impact of feedback on drivers' estimates of performance.

Recent studies focused on driver calibration show that drivers are often miscalibrated, either over confident or under confident, and the magnitude of this miscalibration changes under different conditions. Previous work has demonstrated behavioral and performance benefits of feedback, yet these studies have not explicitly examined the issue of calibration. The objective of this study was to examine driver calibration, i.e., the degree to which drivers are accurately aware of their performance, and determine whether feedback alters driver calibration. Twenty-four drivers completed a series of driving tasks (pace clocks, traffic light, speed maintenance, and traffic cones) on a test track. Drivers drove three different blocks around the test track: (1) baseline block, where no participants received feedback; (2) feedback block, where half of the participants received performance feedback while the other half received no feedback; (3) a no feedback block, where no participants received feedback. Results indicated that across two different calibration measures, drivers were sufficiently calibrated to the pace clocks, traffic light, and traffic cone tasks. Drivers were not accurately aware of their performance regarding speed maintenance, though receiving feedback on this task improved calibration. Proper and accurate measurements of driver calibration are needed before designing performance feedback to improve calibration as these feedback systems may not always yield the intended results.

Scrolling and driving: how an MP3 player and its aftermarket controller affect driving performance and visual behavior.

OBJECTIVE: The aim of this study was to assess how scrolling through playlists on an MP3 player or its aftermarket controller affects driving performance and to examine how drivers adapt device use to driving demands. BACKGROUND: Drivers use increasingly complex infotainment devices that can undermine driving performance. The goal activation hypothesis suggests that drivers might fail to compensate for these demands, particularly with long tasks and large search set sizes. METHOD: A total of 50 participants searched for songs in playlists of varying lengths using either an MP3 player or an aftermarket controller while negotiating road segments with traffic and construction in a medium-fidelity driving simulator. RESULTS: Searching through long playlists (580 songs) resulted in poor driving performance and required more long glances (longer than 2 s) to the device compared with other playlist lengths. The aftermarket controller also led to more long glances compared with the MP3 player. Drivers did not adequately adapt their behavior to roadway demand, as evident in their degraded driving performance. No significant performance differences were found between short playlists, the radio-tuning task, and the no-task condition. CONCLUSION: Selecting songs from long playlists undermined driving performance, and drivers did not sufficiently adapt their use of the device to the roadway demands, consistent with the goal activation hypothesis. The aftermarket controller degraded rather than enhanced performance. APPLICATION: Infotainment systems should support drivers in managing distraction. Aftermarket controllers can have the unintended effect of making devices carried into the car less compatible with driving.These results can motivate development of new interfaces as alternatives to scrolling lists.