Interaction between pedestrians and automated vehicles: A Wizard of Oz experiment

Automated vehicles (AVs) will be introduced on public roads in the future, meaning that traditional vehicles and AVs will be sharing the urban space. There is currently little knowledge about the interaction between pedestrians and AVs from the point of view of the pedestrian in a real-life environment. Pedestrians may not know with which type of vehicle they are interacting, potentially leading to stress and altered crossing decisions. For example, pedestrians may show elevated stress and conservative crossing behavior when the AV driver does not make eye contact and performs a non-driving task instead. It is also possible that pedestrians assume that an AV would always yield (leading to short critical gaps). This study aimed to determine pedestrians’ crossing decisions when interacting with an AV as compared to when interacting with a traditional vehicle. We performed a study on a closed road section where participants (N = 24) encountered a Wizard of Oz AV and a traditional vehicle in a within-subject design. In the Wizard of Oz setup, a fake ‘driver’ sat on the driver seat while the vehicle was driven by the passenger by means of a joystick. Twenty scenarios were studied regarding vehicle conditions (traditional vehicle, ‘driver’ reading a newspaper, inattentive driver in a vehicle with “self-driving” sign on the roof, inattentive driver in a vehicle with “self-driving” signs on the hood and door, attentive driver), vehicle behavior (stopping vs. not stopping), and approach direction (left vs. right). Participants experienced each scenario once, in a randomized order. This allowed assessing the behavior of participants when interacting with AVs for the first time (no previous training or experience). Post-experiment interviews showed that about half of the participants thought that the vehicle was (sometimes) driven automatically. Measurements of the participants’ critical gap (i.e., the gap below which the participant will not attempt to begin crossing the street) and self-reported level of stress showed no statistically significant differences between the vehicle conditions. However, results from a post-experiment questionnaire indicated that most participants did perceive differences in vehicle appearance, and reported to have been influenced by these features. Future research could adopt more fine-grained behavioral measures, such as eye tracking, to determine how pedestrians react to AVs. Furthermore, we recommend examining the effectiveness of dynamic AV-to-pedestrian communication, such as artificial lights and gestures.     

Bio-inspired intent communication for automated vehicles

Various external human-machine interfaces (eHMIs) have been proposed that communicate the intent of automated vehicles (AVs) to vulnerable road users. However, there is no consensus on which eHMI concept is most suitable for intent communication. In nature, animals have evolved the ability to communicate intent via visual signals. Inspired by intent communication in nature, this paper investigated three novel and potentially intuitive eHMI designs that rely on posture, gesture, and colouration, respectively. In an online crowdsourcing study, 1141 participants viewed videos featuring a yielding or non-yielding AV with one of the three bio-inspired eHMIs, as well as a green/red lightbar eHMI, a walk/don’t walk text-based eHMI, and a baseline condition (i.e., no eHMI). Participants were asked to press and hold a key when they felt safe to cross and to answer rating questions. Together, these measures were used to determine the intuitiveness of the tested eHMIs. Results showed that the lightbar eHMI and text-based eHMI were more intuitive than the three bio-inspired eHMIs, which, in turn, were more intuitive than the baseline condition. An exception was the bio-inspired colouration eHMI, which produced a performance score that was equivalent to the text-based eHMI when communicating ‘non-yielding’. Further research is necessary to examine whether these observations hold in more complex traffic situations. Additionally, we recommend combining features from different eHMIs, such as the full-body communication of the bio-inspired colouration eHMI with the colours of the lightbar eHMI.     

International study on the importance of communication between automated vehicles and pedestrians

The market launch of automated vehicles will take place in complex mixed traffic containing pedestrians and other non-automated drivers. Hand gestures, eye contact or similar informal communication strategies to human road users will not be available without a human car driver. Road crossing studies show that people are feeling confused and unsafe without such feedback. Additional external signaling devices have the aim to increase the perception of safety by providing auditory or visual feedback for road users. Due to the international relevance of this topic, we surveyed participants from six countries on the importance of communication. Our results reveal that intention messages are more important than the status signal. The importance of communication is independent of the time of day, traffic density and number of pedestrians. Cross-group analysis indicates a match of 72.97% between the tested nationalities on which kind of message types an automated vehicle should be able to communicate.     

Two-step communication for the interaction between automated vehicles and pedestrians

An important challenge of automated vehicles (AV) will be the cooperative interaction with surrounding road users such as pedestrians. One solution to compensate for the missing driver-pedestrian interaction might be explicit communication via external human machine interfaces (eHMIs). Additionally, implicit communication such as a vehicle pitch motion might support AVs when interacting with pedestrians. While previous work explored various explicit and implicit communication cues, these concepts communicated the intention of the AV at one single time point. Currently, empirical findings on two-step communication lack so far. In this study, we empirically test the effect of a two-step AV communication that uses an implicit cue at a long distance and subsequently provides an implicit or explicit cues at a short distance. We compared its efficiency to single-step communication concepts providing implicit or explicit cues at the shorter distance only. To explore whether the right communication cue is used at the right distance, we analyzed pedestrians’ fixations while approaching an AV using an eye tracking device.We conducted a virtual reality study (N = 30) with AV communication concept that provided an active pitch motion or an eHMI and compared them with a two-step AV communication concept that provided an additional active pitch motion at a long distance when approaching the pedestrian. Furthermore, we recorded pedestrians’ fixation behavior while the AV approached.Consistently to previous work, single-step AV communication showed a beneficial effect on crossing behavior. Pedestrians initiated their crossing earlier while approaching an AV with an active pitch motion or an eHMI compared to the baseline condition. While active pitch motion reduced subjective safety feeling, eHMI increased it. However, the two-step communication concept did not further improve pedestrians’ crossing initiation times and their safety feeling. The pattern of fixation behavior differed as a function of AV distance. When the approaching AV was far away, pedestrians exclusively looked at the environment. During the approach, pedestrians gradually fixated the bumper and the hood and only then the windshield of the AV. Hence, it seems to be useful to present an AV intent communication at a certain distance from the pedestrian. These findings posit the importance of considering pedestrians’ fixation behavior when developing communication concepts between AVs and pedestrians.     

Teenage bicyclists' perceptions toward automated vehicles and their associated traffic infrastructure: A focus group discussion

Automated vehicles (AVs) can improve traffic safety for vulnerable road-users like bicyclists. It is most likely that current young people will be the ones to use these vehicles and interact with them. However, very few studies have focused on bicyclist-AV interaction, with little to no inclusion of teenage bicyclists. This research used a virtual focus group study with 25 teenage bicyclists in six groups. Participants were presented with potential designs of infrastructures and communicating interfaces, they discussed pros and cons for each design, and answered multiple surveys. Overall, teenage bicyclists showed positive perceptions toward AVs. They preferred spacious lanes for bicyclists and physical barriers separating AVs and bicyclists. Teenagers chose visual interfaces with familiar icons; nevertheless, they recommended both visual and audible interfaces to ensure bicyclists’ attention and address the need of visually and audibly impaired populations. Future researchers and stakeholders will be benefited from the methodology and outcomes of this research.     

Sharing the road with autonomous vehicles: A qualitative analysis of the perceptions of pedestrians and bicyclists

Public perception assessment is important for gaining a better understanding of the acceptance of autonomous vehicles (AVs) and identifying potential ways to resolve public concerns. This study investigated how pedestrians and bicyclists perceived AVs based on their knowledge and road sharing experiences, applying a combined inductive and deductive data analysis approach. Survey responses of pedestrians and bicyclists in Pittsburgh, Pennsylvania, USA collected by Bike Pittsburgh (BikePGH) in 2019, were analyzed in this research. AVs following traffic rules appropriately and AVs driving safer than the human drivers were the most notable positive perceptions towards AVs. Pedestrians and bicyclists showed comparatively fewer negative perceptions towards AVs than positive perceptions. Negative perceptions mostly included a lack of perceived safety and comfort around AVs and trust in the AV technology. Respondents also concerned about AV technology issues (e.g., slow and defensive driving, disruptive maneuver), while sharing the road with AVs. Perceptions of the respondents were significantly influenced by their views on AV safety, familiarity with the technology, the extent respondents followed AV on the news, and household automobile ownership. Regulating AV movement on roadways, developing safety assessment guidelines, and controlling oversights of improper practices by AV companies were the major suggestions from the survey participants. Findings of this study might help AV companies to identify potential improvement needed in AV technology to increase pedestrians and bicyclists acceptance, and policymakers to develop policy guidelines to ensure safe road sharing among pedestrians, bicyclists, and AVs.     

Cautious behaviors of pedestrians while crossing narrow streets: Exploration of behaviors using virtual reality experiments

This study explores the cautious behaviors of pedestrians in a typical local street environment using virtual reality (VR)-based experiments under various physical safety design scenarios for roadways. The built environment of this study focused on narrow local roads where frequent daily walking occurs within a neighborhood. VR experiments can provide an objective and accurate measurement of pedestrian behaviors, thus improving the understanding of complicated pedestrian behaviors. Based on experimental data from 200 university students, we identified pedestrians’ crossing behavior that is cautionary or risky concerning various physical safety designs of streets. This study found that there are trade-off relationships between various behaviors which should be systematically studied to produce safer street design guidelines. Furthermore, as the contexts and sequences matter in behaviors for intersection crossing, the interpretation of behaviors should carefully consider the context of built environments and sequential decisions made by pedestrians. This sequential understanding of before- and during-crossing behaviors and their connections expands our knowledge of pedestrians’ crossing behaviors.     

Public acceptance of driver state monitoring for automated vehicles: Applying the UTAUT framework

Driver state monitoring (DSM) systems aim to measure driver/occupant state, considering factors such as fatigue, workload, attentiveness, and wellbeing. They are influential for some vehicles on the road today, but as we move towards higher levels of automation their use is expected to become even more important. Uncertainty around public perception of these systems is a potentially limiting factor, with potential concerns for privacy, data storage, perceived utility, and reliability amongst other things posing potential threats. A survey was conducted based on the Universal Theory of Acceptance and Use of Technology (UTAUT) framework, which collected 311 individual responses to explore the acceptability of this technology in specific relation to conditionally and partially automated vehicles. This paper identified that the factors of effort expectancy, performance expectancy, social influence, and attitudes towards using new technology are all positively related to overall behavioural intention, whereas anxiety is negatively related. Other demographic influences are discussed, and recommendations made for future research and marketing/implementation of DSM systems to ensure acceptance by future users.     

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.     

Car-following behavioural adaptation when driving next to automated vehicles on a dedicated lane on motorways: A driving simulator study in the Netherlands

Automated vehicles (AVs) are expected to improve traffic flow efficiency and safety. The deployment of AVs on motorways is expected to be the first step in their implementation. One of the main concerns is how human drivers will interact with AVs. Dedicating specific lanes to AVs have been suggested as a possible solution. However, there is still a lack of evidence-based research on the consequence of dedicated lanes for AVs on human drivers’ behavior. To bridge this research gap, a driving simulator experiment was conducted to investigate the behavior of human drivers exposed to different road design configurations of dedicated lanes on motorways. The experiment sample consisted of 34 (13 female) licensed drivers in the age range of 20–30. A repeated measures ANOVA was applied, which revealed that the type of separation between the dedicated lane and the other lanes has a significant influence on the behavior of human drivers driving in the proximity of AV platoons. Human drivers maintained a significantly lower time headway (THW) when driving in the proximity of a continuous access dedicated lane as compared to a limited-access dedicated lane with a guardrail separation for AV platoons. A similar result was found for the limited-access dedicated lane in comparison to the limited-access dedicated lane with guardrail separation. Moreover, the results regarding the empirical relationships between THW and sociodemographic variables indicate a significant THW difference between males and females as well as a significant inverse relationship between THW and the years of driving experience.     

Exploring the acceptance of connected and automated vehicles: Focus group discussions with experts and non-experts in transport

The successful deployment of connected and automated vehicles (CAVs) will largely depend on public opinion. Expectations and concerns are essential components driving the speed of market uptake and final adoption of these technologies. We have studied user expectations and concerns, as well as their provenance, by conducting a series of Focus Group (FG) discussions with transport area experts and non-expert participants, in Italy, Germany, and Spain. Together with user acceptance, potential advantages and disadvantages that CAVs may bring at a societal level were explored. Results show that benefits like increased safety and accessibility and improved travel experience for both driver and passengers could support CAVs’ deployment. Nevertheless, a variety of concerns were raised during the discussions, related to privacy, responsibility in case of an accident, and increase in maintenance and repair costs. These aspects could significantly hamper or delay CAVs acceptability and need to be carefully considered by stakeholders. The reported insights from the FG discussions and the fact that some participants noted positive changes of their initial idea of CAVs due to their participation in the discussion, exemplify the importance of citizen engagement activities to address mobility challenges.     

The impact of a dedicated lane for connected and automated vehicles on the behaviour of drivers of manual vehicles

Connected and automated vehicles (CAVs) are expected to enhance traffic efficiency by driving at shorter time headways, and traffic safety by shorter reaction times. However, one of the main concerns regarding their deployment is the mixed traffic situation, in which CAVs and manually driven vehicles (MVs) share the same road.This study investigates the behavioural adaptation of MV drivers in car-following and lane changing behaviour when they drive next to a dedicated lane (DL) for CAVs and compares that to a mixed traffic situation. The expectation is that in a mixed traffic situation, the behavioural adaptation of MV drivers is negligible due to lower exposure time and scarce platoons, while concentrating the CAVs on one dedicated lane may cause significant behavioural adaptation of MV drivers due to a higher exposure time and conspicuity of CAV platoons.Fifty-one participants were asked to drive an MV on a 3-lane motorway in three different traffic scenarios, in a fixed-base driving simulator: (1) Base, only MVs were present in traffic, (2) Mixed, platoons of 2–3 CAVs driving on any lane and mixed with MVs, (3) DL, platoons of 2–3 CAVs driving only on a DL. The DL was recognizable by road signs and a buffer demarcation which separated the DL from the other lanes. A moderate penetration rate of 43% was assumed for CAVs.During the drives, the car following headways and the accepted merging gaps by participants were collected and used for comparisons of driving behaviour in different scenarios.Based on the results, we conclude that there is no significant difference in the driving behaviour between Base and Mixed scenarios at tested penetration rate, confirming our research expectation. However, in DL scenario, MV drivers drove closer to their leaders specially when driving on the middle lane next to the platoons and accepted shorter gaps (up to 12.7% shorter at on-ramps) in lane changing manoeuvres. Dedicating a lane to CAVs increases the density of CAV platoons on one lane and consequently their conspicuity becomes higher. As a result, MV drivers are influenced by CAV platoons on a DL and imitate their behaviour.The literature suggests that dedicating a lane to CAVs improves the traffic efficiency by providing more possibilities for platooning. This study shows that implementing such a solution will affect the driving behaviour of human drivers. This should be taken into consideration when evaluating the impacts of dedicated lanes on traffic efficiency and traffic safety.     

Reducing conflicts between motor vehicles and pedestrians: the separate and combined effects of pavement markings and a sign prompt

The effects of a symbolic "yield here to pedestrians" sign and advance yield pavement markings on pedestrian/motor vehicle conflicts, motorists' yielding behavior, and the distance motorists' yield in advance of crosswalks were evaluated at multilane crosswalks at uncontrolled T intersections. In Experiment 1, the sign, when used alone, reduced pedestrian/motor vehicle conflicts and increased motorist yielding distance. The use of fluorescent yellow-green sheeting as the background of the sign did not increase the effectiveness of the sign. Further reductions in pedestrian/motor vehicle conflicts and further increases in yielding distance were associated with the addition of advance yield pavement markings. In Experiment 2, advance yield pavement markings, when used alone, were as effective in reducing pedestrian/motor vehicle conflicts and increasing yielding distance as the sign combined with pavement markings. These data suggest that the pavement markings were the essential component for reducing conflicts and increasing yielding distance.     

Functional assessment, collaboration, and evidence-based treatment: Analysis of a team approach for addressing challenging behaviors in young children

This study examined the effects of functional assessment and positive behavior support on classroom behaviors of young children. An experimental program, entitled FACET, was implemented by school-based teams in pre-kindergarten through first-grade classrooms. Observations of child behaviors and classroom variables were compared between experimental and control classrooms. Results indicate that children in FACET classrooms made significant gains from baseline to post-intervention and exhibited a higher occurrence of positive behaviors and fewer negative behaviors compared to control children. Behavior gains were positively correlated with the level of treatment fidelity. These findings support the effectiveness of an intervention that incorporates functional assessment, collaboration, and evidence-based treatment with young children who exhibit challenging behaviors.     

Lessons for future research: two experiments failed to reproduce a relationship between achievement motivation and autobiographical memory distortion

ABSTRACT

Previous research (Sharman & Calacouris, 2010. Motivated imagination inflation: Implicit and explicit motives predict imagination inflation for achievement and affiliation events. Experimental Psychology, 57, 77–82) found that participants’ achievement-motivation was associated with the inflation of memory and confidence for unlikely achievement-related events in childhood. Similarly, other research has shown correlations between achievement motivation and grade inflation. In the current studies, we experimentally investigate the effect of false feedback and achievement-motivation on memory distortion for an unlikely childhood event (e.g. inventing an important device). In Experiment 1, we found that false feedback did have an effect, but contrary to previous research, self-reported achievement-motivation was not a statistically significant correlate of memory distortion. In Experiment 2, we again found a main effect for false feedback, no main effect of motivation, and an interaction. Both Experiments did not find, as earlier research had, a significant relationship between achievement-motivation and achievement-related memory distortion. We suggest others use different methods to ours when attempting to demonstrate a causal relationship between motivation and false memories.     

Exploring classical conditioning for strengthening the links between semantic and lexical representations in pure anomia: Preliminary findings from a single case study

The same language symptom might arise at different functional loci in people with aphasia. Therefore, it is plausible that different therapeutic interventions should be adopted to approach the same difficulties in different patients. Although this point of view is still widely accepted, recently the focus has shifted from the functional locus of a rehabilitative intervention to the mechanisms of action underlying the relearning process. We maintain that both aspects should be taken into account when programming a rehabilitative intervention; furthermore, investigating relearning mechanisms might shed new light on the functional architecture of the disrupted processes. Here, we investigated, in a single case study, whether classical conditioning was a suitable relearning paradigm for targeting word‐finding difficulties in pure anomia, that is in a patient with an impairment in accessing intact output lexical representations from a spared semantic system. Using a word‐repetition task on picture presentation, we contrasted a condition in which the stimulus onset asynchrony between word and picture stimuli was well suited to produce classical conditioning with a condition in which repetition training could not benefit from this learning mechanism. Only classical conditioning training exerted a significant, long‐lasting effect on our patient's naming skill. Tentative implications of our results for the functional architecture of single‐word processing are discussed.     

A narrative review: arguments for a collaborative approach in mental health between traditional healers and clinicians regarding spiritual beliefs

This review explores the possibility of a more collaborative approach between mental health clinicians and traditional healers, from a clinical psychology perspective, for clients with spiritual beliefs. Spiritual beliefs are incorporated into the identity and functioning of clients within a cultural context and prevalence rates reveal this is not uncommon. It is argued that working collaboratively would address many access difficulties to mental health services and support is generated through a number of studies and case reports in the United Kingdom, worldwide and across cultures. This approach appears to be in accordance with current theories of acculturation. The problems in the current system when working non-collaboratively are also explored. Counter arguments and pragmatic difficulties of collaboration have been discussed. Research in the United Kingdom is limited and it is suggested that more research is needed in the field. Pragmatic solutions are suggested to stimulate discussion.     

Associations between attention,affect and cardiac activity in a single yoga session for female cancer survivors: An enactive neurophenomenology-based approach

Yoga practice is reported to lead to improvements in quality of life, psychological functioning, and symptom indices in cancer survivors. Importantly, meditative states experienced within yoga practice are correlated to neurophysiological systems that moderate both focus of attention and affective valence. The current study used a mixed methods approach based in neurophenomenology to investigate associations between attention, affect, and cardiac activity during a single yoga session for female cancer survivors. Yoga practice was associated with a linear increase in associative attention and positive affective valence, while shifts in cardiac activity were related to the intensity of each yoga sequence. Changes in attention and affect were predicted by concurrently assessed cardiac activity. Awareness of breathing, physical movement, and increased relaxation were reported by participants as potential mechanisms for yoga’s salutary effects. While yoga practice shares commonalities with exercise and relaxation training, yoga may serve primarily as a promising meditative attention-affect regulation training methodology.     

Reduction of appeasement‐related affect as a concomitant of diazepam‐induced aggression: evidence for a link between aggression and the expression of self‐conscious emotions

Aggressive responding following benzodiazepine ingestion has been recorded in both experimental and client populations, however, the mechanism responsible for this outcome is unclear. The goal of this study was to identify an affective concomitant linked to diazepam‐induced aggression that might be responsible for this relationship. Thirty males (15 diazepam and 15 placebo) participated in the Taylor Aggression Paradigm while covertly being videotaped. The videotapes were analyzed using the Facial Action Coding System with the goal of identifying facial expression differences between the two groups. Relative to placebo participants, diazepam participants selected significantly higher shock settings for their opponents, consistent with past findings using this paradigm. Diazepam participants also engaged in significantly fewer appeasement expressions (associated with the self‐conscious emotions) during the task, although there were no group differences for other emotion expressions or for movements in general. Aggr. Behav. 35:203–212, 2009. © 2008 Wiley‐Liss, Inc.