Pedestrians’ road crossing behaviour in front of automated vehicles: Results from a pedestrian simulation experiment using agent-based modelling

The objective of this research is to explore the relation between personal characteristics of pedestrians and their crossing behaviour in front of an automated vehicle (AV). For this purpose, a simulation experiment was developed using Agent-Based Modelling (ABM) techniques. Sixty participants were asked to cross the road in a virtual environment displayed on a computer screen, allowing to record their crossing behaviour when in the presence of AVs and conventional vehicles (CVs). In some experimental configurations, the AVs communicated their intention to continue or not to continue their trajectories through the use of lights. The ABM allowed controlling the behaviour of the vehicles when interacting with the simulated avatar of the respondents. The subjects of the experiment were also asked to fill in a questionnaire about usual behaviour in traffic, as well as attitudes and risk perceptions toward crossing roads. The questionnaire data were used to estimate individual specific behavioural latent variables by means of principal component analysis which resulted in three main factors named: violations, lapses, and trust in AVs. The results of generalized linear mixed models applied to the data showed that besides the distance from the approaching vehicle and existence of a zebra crossing, pedestrians’ crossing decisions are significantly affected by the participants’ age, familiarity with AVs, the communication between the AV and the pedestrian, and whether the approaching vehicle is an AV. Moreover, the introduction of the latent factors as explanatory variables into the regression models indicated that individual specific characteristics like willingness to take risks and violate traffic rules, and trust in AVs can have additional explanatory power in the crossing decisions.     

Effect of external HMI for automated vehicles (AVs) on drivers’ ability to infer the AV motion intention: A field experiment

A field experiment was conducted aiming to shed light on how drivers negotiate an ambiguous traffic situation when encountering an autonomous vehicle (AV) in the presence of a yielding intention signal (AV with eHMI) or not (AV without eHMI). A traffic conflict scenario was created with two opposing vehicles instructed to perform a left turn at a four-way junction, at the same point in time. Forty participants were assigned to two groups encountering either an AV with eHMI or an AV without eHMI. To check for equivalence across the two groups, both groups also encountered a conventional vehicle (CV). Results showed that the two groups performed similarly during encounters with a CV. During encounters with AV, however, participants provided with the eHMI maintained higher speed before the AV and finished their maneuver quicker than when they were not provided with eHMI. Additionally participants provided with eHMI rated higher their ability to infer the AV intention before coming to a full-stop than those provided without eHMI. The above findings indicate that the presence of eHMI on AV can accelerate drivers’ inferences about yielding intention of an AV, and have the potential to optimize AV-driver interaction in ambiguous traffic situations.     

“Why would they call me an orphan when I have parents”: Care leavers’ experiences of labelling and stereotyping whilst living in residential care facilities in Zimbabwe

Care leaving research has focused on the experiences of young people when they make the transition from residential care facilities (RCCFs) back into mainstream society. Past research has found evidence of social exclusion and documents challenges that care leavers face when re-entering the society when they age-out of care. Some challenges include a lack of preparation for independent living, including limited financial, housing and employment support. There exists a gap in care leaving literature about the extent to which the labelling and stereotyping of care leavers during their time in RCCFs affects their transitions into adulthood. This paper presents an analysis of interviews conducted with care leavers from six childcare facilities in Zimbabwe (n = 30). The paper argues that the labelling and stereotyping of care leavers has a negative effect on how they are accepted and reintegrated into the society. The thematic analysis of the data provides clear evidence of some of the negative labels such as being called an“orphan” in the case of some non-orphans in RCCFs, and the negative stereotypes which stuck with the care leavers years into their adulthood. These labels and stereotypes also affected care leavers’ own perceptions of themselves as well as their interpersonal relationships with others. The paper identifies some implications for social work practice and makes recommendations towards the promotion of a more positive social image of care leavers.