What and how to tell beforehand: The effect of user education on understanding,interaction and satisfaction with driving automation

The success of introducing automated driving systems to consumers will depend on an appropriate understanding and human-automation interaction with this technology. Educating users on driving automation technology bears the potential to attain these two requirements. In a driving simulator study, we investigated the effects of user education on mental models, human-automation interaction performance (i.e., time on task, error rate, experimenter rating) and satisfaction with a Human-Machine Interface (HMI) for automated driving. N = 80 participants were randomly assigned to one of three different user education conditions or to a baseline. Subsequently, they completed several driver-initiated control transitions between manual, Level 2 (L2), and Level 3 (L3) automated driving. The results revealed that user education promoted an accurate evolution of mental models for driving automation. These, in turn, facilitated interaction performance in transitions from manual to both L2 and L3 automated driving. There was no comparable influence of prior education on performance in transitions between the automation levels. Due to the performance enhancing effects of user education, no further improvements of interaction performance were observed for educated users in comparison to uneducated users. There was no effect of user education on satisfaction. The current findings emphasize the necessity to provide information about automated vehicle HMIs to first-time users to support accurate understanding and behavior. Based on the current findings, we propose conceptual approaches to teach users and derive implications for user studies on automated vehicle HMIs.     

Examining human attitudes toward shared mobility options and autonomous vehicles

This paper presents a comprehensive analysis of people’s attitudes toward shared mobility options and autonomous vehicles (AVs), with a focus on the underlying patterns and potential determinants. A stated preference (SP) survey was designed and implemented in the U.S. Four sets of questions were included in the questionnaire, each focused on one unique aspect of user attitudes, including a) preferences for mobility options and lifestyle (such as overall view of driving, factors in mode choice decisions and technology engagement), b) perceived benefits and concerns of shared mobility option, c) reasons toward or against private vehicle ownership, and d) motivations for and desired features of AVs. A structural equations model was developed to identify latent attitudinal factors and examine the correlations between the latent attitudes (as the endogenous variables) and the observed covariates (including the socio-economic and demographic characteristics, and users’ current mobility profile, such as mode use frequency, travel distance, and trip fare). The model identified eleven latent factors that represent various aspects of attitudes toward AVs and shared mobility options. The findings could be used by policymakers and Transportation Network Companies (TNCs) to a) recognize the users’ latent attitudes, b) understand the underlying patterns of attitudes, c) implement plans and policies more efficiently, d) guide or influence users’ perceptions, and e) enhance travel behavior models. This study lays the foundation for further analysis on understanding user acceptance and adoption of these emerging mobility options, which is essential to estimate the likelihood and magnitude of behavior shifts in the era of automated, connected and shared mobility.     

Exploring the characteristics of potential and current users of mobility scooters,among older people in Israel

Recognizing the decline in the ability of older people to serve as vehicle drivers and their physical limitations for long walks, mobility scooters are considered as an alternative mobility means for older people. An increasing popularity of scooters is recently being observed in Israel, raising safety concerns. This study explored the characteristics of potential users of mobility scooters among older people in Israel and the behaviours of their current users, by means of an opinion survey and field observations in urban areas. The opinion survey applied structured interviews, with 110 persons aged 65+. The survey's results showed that most people agreed that scooters may improve their mobility and quality of life. However, they expressed a relatively low willingness to use scooters, mostly, due to the preference for private cars but also the lack of appropriate infrastructure for safe scooter travel in the city. An increasing potential for scooters' use was associated with ages 70–84, people who are aware of their health problems and less involved in physical activities but still maintain an active lifestyle, living independently and appreciating scooter benefits. The observations included 55 video-records with older scooter riders. They showed that regardless the types of urban road or junction, the majority of scooter riders behaved like a vehicle, i.e. travelled on the roadway. Scooters' moving on a sidewalk did not create conflicts with pedestrians, while scooters travelling on the roads sometimes disturbed vehicle flows and created dangerous situations. To ensure safety of the scooter users, their travels on the sidewalks should be stimulated and, thus, appropriate adjustments of urban infrastructure are required.     

External communication of automated vehicles in mixed traffic: Addressing the right human interaction partner in multi-agent simulation

The urban traffic system is most likely to change in the next years to a mixed traffic with human drivers, vulnerable road users, and automated vehicles. In the past, the development of external communication approaches for automated vehicles focused on scenarios where an automated vehicle communicates with either a pedestrian or a human driver. However, interactions with more than one traffic partner are more realistic. Therefore, a study with 42 participants was conducted with a multi-agent simulation in which an automated vehicle interacted simultaneously with two participants, a pedestrian and a driver of a manual vehicle. In this study, two main scenarios were investigated in order to evaluate the safety and efficiency of the interactions and to determine whether the human road users feel correctly addressed. In one scenario, the pedestrian had to cross the road in front of the automated and the manual vehicle, which were approaching from different sides. In the other, the manual vehicle had to drive through a bottleneck in front of the oncoming automated vehicle, while the pedestrian had to cross the road after both vehicles passed. The communication approach of the automated vehicle consisted of implicit signals using a speed profile and lateral offset within its lane, and explicit signals using an external human–machine interface. The results of the study show that no collisions were observed in terms of safety and no significant negative effects on efficiency were measured. However, in contrast to single agent interactions, a majority of participants felt wrongly addressed in situations where the automated vehicle signals the right-of-way to the other human road user. It can be concluded that the communication approach of the automated vehicle needs to be modified in order to address certain road users more clearly.     

User gesticulation inside an automated vehicle with external communication can cause confusion in pedestrians and a lower willingness to cross

Automated vehicles are expected to require some form of communication (e.g., via LED strip or display) with vulnerable road users such as pedestrians. However, the passenger inside the automated vehicle could perform gestures or motions which could potentially be interpreted by the pedestrian as contradictory to the outside communication of the car. To explore this conflict, we conducted an online experiment (N = 59) with different message types (no message, intention, command), gestures (no gesture, wave, stop), and user positions (driver, co-driver) and measured the pedestrian’s confidence in crossing. Our results show that certain combinations (e.g., car indicates cross while the user in the driver seat gestures stop) confused the pedestrian, resulting in significantly lower confidence to cross. We further show that designing intention-based external communication led to less confusion and a significantly higher intention to cross.     

Virtually the same? Analysing pedestrian behaviour by means of virtual reality

Thanks to technological advancements, virtual reality has become increasingly flexible and affordable, resulting in a growing number of user studies conducted in virtual environments. Pedestrian simulators, visualizing traffic scenarios from a pedestrians’ perspective, have thereby emerged as a powerful tool in traffic safety research. However, while both the interest in this technology and the concern for vulnerable road users is high, a systematic overview of research employing pedestrian simulators has not been provided so far.The present literature survey is based on 87 studies published during the past decade, investigating pedestrian behaviour by means of virtual traffic scenarios. Results were categorized according to the research question, technical setup, experimental task, and participant sample. Identifying trends and gaps in knowledge and highlighting differences between methodological approaches, this work serves as an assessment of the current state and a baseline from which to develop future research questions. It aims to demonstrate both opportunities and challenges of this relatively new methodology. Thereby, it is hoped to foster the awareness of existing limitations, support the reasonable interpretation of the available data, and guide pedestrian research towards reliable and generalizable insights enhancing pedestrian mobility, comfort, and safety.     

Investigating relationships among perceptions of yielding,safety, and comfort for pedestrians in unsignalized crosswalks

Interactions with other road users influence the perceived safety and comfort of pedestrians. Yet the relationships among perceptions of yielding, safety, and comfort are poorly understood. To enhance understanding of these key concepts, the objectives of this study are to determine how perception of pedestrian safety at unsignalized crosswalks differs from perception of comfort, and the relationship of each with perception of yielding. A generalized structural equations model is developed using data from an online survey in which 366 participants (i.e., “perceivers”) rated yielding, safety, and comfort for sample videos of pedestrian interactions with motor vehicles and bicycles. Results show that an individual’s perception of yielding plays a crucial role in mediating the effects of interaction attributes (e.g., vehicle speed, proximity) and perceiver attributes (e.g., travel habits) on their perceptions of pedestrian safety and comfort. For example, people who bicycle more frequently perceive pedestrians as more comfortable than people who walk more frequently, rooted in misalignment on what constitutes adequate yielding. Strategies to address pedestrian comfort can focus on a set of key yielding behaviors by drivers and cyclists – particularly allowing the pedestrian to cross first. Motor vehicle drivers must exhibit stronger yielding behavior (e.g., allow a larger time gap) than bicycles to achieve the same level of perceived pedestrian safety and comfort. Although perceptions of safety and comfort are strongly related and similarly impacted by yielding, researchers should be cautious about using the concepts interchangeably because they are differently impacted by attributes of the interaction and perceiver.     

The conditioned anticipation of people (CAP) model of driving in urban spaces

Despite significant gains in overall collision rates, pedestrian and bicycle safety in complete street environments remains an on-going challenge. However, urban areas with the most risk exposure for pedestrians continue to maintain lower incident rates than their suburban counterparts (“Dangerous by Design” 2021). Under most driving circumstances, the over-rehearsed nature of driving leads to a psychological state similar to self-hypnosis, where attention is subconsciously maintained on the driving task while metacognitive awareness is minimized or eliminated. This state continues until some type of conflict, uncertainty, and/or novel stimulus is presented. The primary difference in driver attention in urban environments is postulated to result from the Conditioned Anticipation of People (CAP). Based on the human neurological predisposition to recognize and fixate on human faces and figures, we hypothesize that in areas where drivers have been conditioned to expect human presence, low-level metacognition is preemptively re-engaged to address their presence, resulting in higher attentional resource expenditure and increased distraction management. Such conditioning may be generated by contextual features common to pedestrian-friendly environments but, necessarily, must be reinforced over time by the Actual Presence of People (APP). CAP driver engagement is limited by the perceptual abilities of the driver such that at higher speeds or within wider corridors, the presence of pedestrians is more difficult to perceive. This results in a non-CAP attention pattern, exhibiting minimal metacognitive activity, high levels of automaticity, and reduced attention. This model was generated based on the observation that vulnerable user presence and the roadway contextual features that support the driver's ability to see vulnerable users were related to attention data measured during the SHRP2 Naturalistic Driving Study. Visually discernable features that were associated with vulnerable user presence had relationships with attention and large effect sizes (η² > 0.5). Contextual features that had relationships with vulnerable user presence, but minimal visual impact or interfered with the driver’s ability to see vulnerable users had no relationship to driver attention. This behavioral pattern provides supportive evidence for the proposed model.     

The role of psychological factors on the choice of different driving controls: On manual,partial, and highly automated controls

The present study investigates the role of psychological factors on the choice of three controls (modes) in driving a vehicle, namely highly automated, partially automated, and manual control. Traditional driving habits, resistance to change, and behavioural beliefs were all assessed along with individual and socioeconomic variables. Using survey data (n = 595) of car users, a model was developed to predict the share of different driving controls and determine the effects of psychological variables. Results indicate that up to 55% of people prefer driving with highly automated control, and 30% prefer partially automated control. Behavioural beliefs (e.g., attitudes toward highly automated control) are not as critical to driving control as habits. People with stronger driving habits are less likely to use highly automated controls. A one-unit increase in worry could reduce driving in highly automated control by 5.5% and increase manual control by 4.5%, and those who welcome the new technologies are more likely to prefer highly automated control. Some practical policy solutions are also provided.     

Road user interactions in a shared space setting: Priority and communication in a UK car park

Appropriate communication between road users can lead to safe and efficient interactions in mixed traffic. Understanding how road users communicate can support the development of effective communication methods for automated vehicles. We carried out observations of 66 pedestrian-driver and 124 driver-driver interactions in a shared space setting. Specific actions and reactions of the road users involved were recorded using a novel observation protocol. Overall, results showed that pedestrians’ failure to look towards a driver created the greatest uncertainty in the interaction, with the driver slowing down, but not completely stopping, in response to pedestrians. Looking towards the driver also influenced which road user took priority in driver-driver interactions. Groups of pedestrians were more likely to be given priority than an individual pedestrian, and the use of vehicle-based signals were also associated with taking priority during an interaction. Our observations show the importance of non-verbal communication during road user interactions, highlighting it as an essential area of research in the development of automated vehicles, to allow their safe, cooperative, interactions with other road users. Observations were made on a limited number of interactions to inform challenges facing future automated vehicles. Further work should therefore be done to corroborate and extend our findings, to examine interactions between human road users and automated vehicles in shared space settings.     

Driving at night with a cataract: Risk homeostasis?

Driving with a cataract can be dangerous, especially at night when road lighting and automotive lighting produce glare. Disability glare alters visual performance, while discomfort glare contributes to restricted mobility, with drivers avoiding driving at night. The present study was focused on the visual effects of an early cataract, and aimed at comparing three driving performance indexes at night, under glare conditions, with and without a simulated cataract. Two indexes directly referred to road safety, while a measure could be related to behavioral adaptation.Using a driving simulator, twenty-six participants were asked to drive in simulated night-time conditions, under controlled photometric conditions where the adaptation luminance and the glare level were consistent with a two-lane rural road at night with oncoming traffic. The visual effects of a bilateral cataract were simulated using goggles which were in the range of an early cataract in terms of light scattering, light transmission, visual acuity and contrast sensitivity loss. Participants were asked to avoid virtual pedestrians on the road, both with and without a simulated cataract. Three performance indexes were considered: the rate of pedestrian crashes, the distance to the pedestrian when the participant avoided the crash, and the mean speed, which allowed to control for a possible behavioral adaptation to the reduced visual performance. For a better understanding of the visual functions responsible for the degraded driving behavior, contrast sensitivity and time-to-collision performance were also measured in glare conditions.While simulated cataract resulted in slightly slower speeds, poorer driving performance was observed with the goggles than without, with more pedestrians being hit and shorter stopping distances. Time-to-collision estimates at 90 km/h were found to be predictive of stopping distances with a simulated cataract, while contrast sensitivity in glare conditions at 13 cycles per degree was found to be associated with the occurrence of a crash with cataract.The decrease in speed with a simulated cataract was real but ineffective in terms of driving safety, which suggests that the behavioral adaptation to the degraded visual performance was insufficient. The precise impact of a cataract on driving abilities remains to be further studied, to provide scientific knowledge to help practitioners determine the moment when the individuals should forego driving.     

Comparison of pedestrian behaviors between drivers and non-drivers in Chinese sample

Road safety is a serious problem worldwide. Pedestrians, as the most vulnerable road users, deserve more attention. The aims of this study were to examine the validity of the Chinese version of the pedestrian behavior scale (CPBS) in both driver and non-driver samples, and to compare pedestrian behaviors between the two samples. In addition, we assessed the association of attention with pedestrian behaviors by exploring the relationships among CPBS, Mindful Attention Awareness Scale (MAAS) and Attention-Related Cognitive Errors Scale (ARCES). Two groups were assessed, including 302 members in the population with driving experience and 307 individuals in the non-driver group without driving experience. All participants completed the CPBS, MAAS, and ARCES, and provided sociodemographic parameters. The results showed that the CPBS had acceptable internal consistency and stability structure. More importantly, pedestrian behaviors were significantly different between drivers and non-drivers. Drivers reported significantly less transgressive and aggressive behaviors compared with non-drivers. As for the relationship between attention and pedestrian behavior, the MAAS score showed a significant negative correlation with aggressive behavior in the CPBS among drivers, while the ARCES score had significant positive correlations with all three CPBS factors. In non-drivers, the MAAS score was negatively correlated with aggressive behavior and positively associated with positive behavior; the ARCES score was positively correlated with aggressive behavior.     

Level of service of pedestrian facilities: Modelling human comfort perception in the evaluation of pedestrian behaviour patterns

The paper presents a new methodology for evaluating the quality of operation of pedestrian facilities: the methodology is based on the individual level of comfort perceived by each pedestrian that moves in the area.At each time instant, each pedestrian perceives a comfort level which is a function of the space they feel currently available and of his required space. The required space depends on the subject’s walking direction as well as on physical and psychological factors. The available space depends on the current positions of pedestrians. The proposed methodology quantifies the current discomfort due to pedestrian interactions as a continuous function of the interpersonal distances.The proposed methodology has been applied to empirical data. The experimental data are presented, discussed and compared with widely accepted level of service assessment methods.     

At the intersection of social and cognitive development: internal working models of attachment in infancy

Three visual habituation studies using abstract animations tested the claim that infants' attachment behavior in the Strange Situation procedure corresponds to their expectations about caregiver-infant interactions. Three unique patterns of expectations were revealed. Securely attached infants expected infants to seek comfort from caregivers and expected caregivers to provide comfort. Insecure-resistant infants not only expected infants to seek comfort from caregivers but also expected caregivers to withhold comfort. Insecure-avoidant infants expected infants to avoid seeking comfort from caregivers and expected caregivers to withhold comfort. These data support Bowlby's (1958) original claims-that infants form internal working models of attachment that are expressed in infants' own behavior.     

The impact of leaving a voicemail,environment familiarity,and pedestrian predictability on driving behavior

Talking on a cell phone can impair driving performance, but the dynamics of this effect are not fully understood. We examined the effects of leaving a voicemail message on driving when there are critical driving targets to attend to (crosswalks and pedestrians). Participants engaged in an ecologically-valid “voicemail” task while navigating a virtual environment using a driving simulator. We also examined the potential weakening or strengthening of effects of leaving a voicemail message on driving as the familiarity and predictability of critical targets changed. Participants completed four experimental runs through the same driving environment in a driving simulator. There were two crosswalks, one with a pedestrian entering the roadway and one without a pedestrian and the location of the pedestrian was predictable (the same pedestrian consistently used the same crosswalk) for the first three runs and then unpredictable for the fourth. Half of the participants left voicemail messages using a hands-free headset, while the other half drove in silence. Leaving a voicemail message increased steering deviation and velocity. Drivers who were leaving a voicemail message decelerated for pedestrians in the roadway to a similar speed as drivers who were not leaving a voicemail message, but they were delayed in braking. Drivers who were leaving a voicemail message also had worse memory for roadway landmarks. These effects were relatively stable across runs through the same driving environment, suggesting that familiarity and predictability did not impact the effects of leaving a voicemail message while driving. Therefore, leaving a voicemail message leads to poorer driving behavior; faster speed, variable steering, and worse memory for roadway landmarks. Interestingly, although drivers who were leaving a voicemail message were slower to react to local targets, they slowed as much as drivers who were not leaving a voicemail message and familiarity with the driving environment did not impact the effects of leaving a voicemail message on driving.     

Exploration of mental envelope determinants when pedestrians interact with various mobilities on mixed streets

Mixed traffic of multiple road users may increase when machines and future mobilities are gradually introduced in human society to satisfy the travel and service needs of people. For providing a safe and comfortable walking environment for pedestrians in the mixed streets with various mobilities, this study proposes the envelope theorem based on the contributions and limitations of the previous explorations in human–machine coexistence. The envelope is divided into physical and mental envelopes. The main focus of this study is the mental envelope (ME) which is a psychological boundary used to distinguish the range of comfort and unpleasantness in people’s minds. ME as the expansion of previous interpersonal distance can explain the pedestrian perceptions from different perspectives. This paper discusses the definition, expressions, and applications of ME, and then explores its determinants and relationships by conducting structural equation modeling (SEM) based on the questionnaire survey. The findings may assist to create better road allocation in the future.     

Head-mounted displays for clinical virtual reality applications: pitfalls in understanding user behavior while using technology.

The use of virtual environments with head-mounted displays (HMDs) offers unique assets to the evaluation and therapy of clinical populations. However, research examining the effects of this technology on clinical populations is sparse. Understanding how wearers interact with the HMD is vital. Discomfort leads to altered use of the HMD that could confound performance measures; the very measures which might be used as tools for clinical decision making. The current study is a post-hoc analysis of the relationship between HMD use and HMD comfort. The analysis was conducted to examine contributing factors for a high incidence of simulator sickness observed in an HMD-based driving simulator. Pearson correlation analysis was used to evaluate objective and subjective measures of HMD performance and self-reported user comfort ratings. The results indicated weak correlations between these variables, indicating the complexity of quantifying user discomfort and HMD performance. Comparison of two case studies detailing user behavior in the virtual environment demonstrates that selected variables may not capture how individuals use the HMD. The validity and usefulness of the HMD-based virtual environments must be understood to fully reap the benefits of virtual reality (VR) in rehabilitation medicine.     

Keeping the driver in the loop in conditionally automated driving: A perception-action theory approach

In this paper we investigated if keeping the driver in the perception–action loop during automated driving can improve take-over behavior from conditionally automated driving. To meet this aim, we designed an experiment in which visual exposure (perception) and manual control exposure (action) were manipulated. In a dynamic driving simulator experiment, participants (n = 88) performed a non-driving related task either in a head-up display in the windshield (high visual exposure) or on a head-down display near the gear shift (low visual exposure). While driving, participants were either in an intermittent control-mode with four noncritical take-over situations (high manual control exposure), or in a continuous automation-mode throughout the ride (low manual control exposure). In all conditions, a critical take-over had to be carried out after an approximately 13 min ride. Measurements of take-over behavior showed that only high visual exposure had an effect on hands-on reaction time measurements. Both visual exposure and manual control exposure had small to medium sized main effects on time to system deactivation, the maximum velocity of the steering wheel, and the standard deviation of the steering wheel angle. The combined high visual – and high manual control exposure condition led to 0.55 s faster reaction time and 37% less steering variability in comparison to the worst case low visual – and low manual control exposure condition. Together, results corroborate that maintaining visual exposure and manual control exposure during automated driving can be efficacious and suggest that their positive effects are additive.     

Effects of environmental,vehicle and human factors on comfort in partially automated driving: A scenario-based study

Although it is key to improving acceptability, there is sparse scientific literature on the experience of humans as passengers in partially automated cars. The present study therefore investigated the influence of road type, weather conditions, traffic congestion level, vehicle speed, and human factors (e.g., trust in automated cars) on passenger comfort in an automated car classified as Level 3 according to the Society of Automotive Engineers (SAE). Participants were exposed to scenarios in which a character is driven by an SAE Level 3 automated car in different combinations of conditions (e.g., highway × heavy rain × very congested traffic × vehicle following prescribed speed). They were asked to rate their perceived comfort as if they were the protagonist. Results showed that comfort was negatively affected by driving in downtown (vs. highway), heavy rain, and congested traffic. Interaction analyses showed that reducing the speed of the vehicle improved comfort in these two last conditions, considered either individually or in combination. Cluster analysis revealed four profiles: trusting in automation, averse to speed reduction, risk averse, and mistrusting automation. These profiles were all influenced differently by the driving conditions, and corresponded to varying levels of trust in automated cars. This study suggests that optimizing comfort in automated cars should take account of both driving conditions and human profiles.     

Key challenges in tram/streetcar driving from the tram driver’s perspective – A qualitative study

Tram drivers have a difficult task in controlling one of the heaviest vehicles on the road whilst negotiating a complex road environment with multiple road users. Like all public transport drivers, tram drivers need to ensure passenger safety and to run on time. However, very little research has been conducted evaluating tram driving tasks and even less on evaluating tram drivers opinion on how other road users are affecting tram road safety. Therefore, the aim of this study is to investigate the key tram driving challenges, to identify the key road user factors affecting tram road safety as well as to explore the potential safety improvement initiatives on tram routes from the tram drivers’ viewpoint. The study incorporated five focus groups involving thirty tram drivers in Melbourne. The key themes emerged inductively from focus groups were identified through a data coding process. Outcomes of the focus groups revealed seven major challenges in tram driving: ensuring safety for all people in and around the tram, pressure for running on-time, maintaining constant concentration on roads, predicting other road users’ behavior in advance to avoid any crash incident, preventing passenger falls on board, accepting the operational constraints of trams and managing fatigue workloads. Tram drivers identified that other road users are unaware of safety issues around trams, have a poor understanding of road rules about driving with trams and often violate road rules around trams, and they mentioned this road user behaviors as the key challenges for safe tram driving. Tram drivers proposed rendering greater law enforcement on the tram network to penalize road users who are violating road rules around trams, introducing more safety campaigns and safety education to increase awareness among road users to improve tram road safety. Findings of this research enhance understanding of tram driving challenges, provide an in-depth knowledge of road user factors affecting tram road safety and suggest effective planning strategies for transit agencies to improve road safety.