Cyclists’ Crossing Intentions When Interacting with Automated Vehicles: A Virtual Reality Study

Support systems for cyclists in automated traffic: A review and future outlook

Interaction with vulnerable road users in complex urban traffic environments poses a significant challenge for automated vehicles. Solutions to facilitate safe and acceptable interactions in future automated traffic include equipping automated vehicles and vulnerable road users, such as cyclists, with awareness or notification systems, as well as connecting road users to a network of motorised vehicles and infrastructure. This paper provides a synthesis of the current literature on communication technologies, systems, and devices available to cyclists, including technologies present in the environment and on motorised interaction partners such as vehicles, and discusses the outlook for technology-driven solutions in future automated traffic. The objective is to identify, classify, and count the technologies, systems, and devices that have the potential to aid cyclists in traffic with automated vehicles. Additionally, this study aims to extrapolate the potential benefits of these systems and stimulate discourse on the implications of connected vulnerable road users. We analysed and coded 92 support systems using a taxonomy of 13 variables based on the physical, communicational, and functional attributes of the systems. The discussion frames these systems into four categories: cyclist wearables, on-bike devices, vehicle systems, and infrastructural systems, and highlights the implications of the visual, auditory, motion-based, and wireless modes of communication of the devices. The most common system was cyclist wearables (39%), closely followed by on-bike devices (38%) and vehicle systems (33%). Most systems communicated visually (77%). We suggest that interfaces on motorised vehicles accommodate cyclists with visibility all around the car and incorporate two-way communication. The type of system and the effect of communication modality on performance and safety needs further research, preferably in complex and representative test scenarios with automated vehicles. Finally, our study highlights the ethical implications of connected road users and suggests that the future outlook of transport systems may benefit from a more inclusive and less car-centred approach, shifting the burden of safety away from vulnerable road users and promoting more cyclist-friendly solutions.

The pedestrian behaviour scale: A systematic review of its validation around the world

OBJECTIVE

The Pedestrian Behaviour Scale (PBS) is a self-report questionnaire that distinguishes five dimensions of pedestrian behaviour: violations, errors, lapses, aggressive behaviours and positive behaviours. This study aimed to meet three objectives: to trace the development of the PBS worldwide from 1997 to 2021, to report on its varied uses and to analyse the scientific validation of the different dimensions of pedestrian behaviour reflected by the PBS and its derivatives.

DESIGN/METHODOLOGY

In this systematic literature review, we selected all works that cited the 2013 founding study of the PBS as well as all publications that cited the 2017 US validation of PBS which was frequently replicated around the world. We conducted an online database search using Web of Science, Google Scholar, ResearchGate and PubMed. After excluding duplicates, 116 studies were identified. A total of 30 studies were selected to meet our first two objectives and 14 studies were selected to meet our third objective.

RESULTS

Over time, the PBS has undergone many changes. Overall, we found differences in the scientific validation of this questionnaire depending on the version used, the validation tests performed and the population studied. The original version of the PBS and its Turkish adaptation proved most appropriate for assessing the transgressions dimension. The American version of the PBS proved a suitable alternative but it is more suited to assessing the two independent dimensions of violations and errors. The Chinese version of the PBS (CPBS) proved unsuitable for assessing the lapses dimension, while the original version of the PBS emerged as the best option for assessing aggressive behaviours. The positive behaviour dimension presented many validation difficulties but its assessment by the CPBS seems to be the most appropriate option.

CONCLUSION

As no systematic review of the PBS has been conducted before, researchers can now make an informed choice of methodology quickly and be guided by our recommendations regarding the use and possible improvements of the different validated versions.

Automated vehicles that communicate implicitly: examining the use of lateral position within the lane

It may be necessary to introduce new modes of communication between automated vehicles (AVs) and pedestrians. This research proposes using the AV's lateral deviation within the lane to communicate if the AV will yield to the pedestrian. In an online experiment, animated video clips depicting an approaching AV were shown to participants. Each of 1104 participants viewed 28 videos twice in random order. The videos differed in deviation magnitude, deviation onset, turn indicator usage, and deviation-yielding mapping. Participants had to press and hold a key as long as they felt safe to cross, and report the perceived intuitiveness of the AV's behaviour after each trial. The results showed that the AV moving towards the pedestrian to indicate yielding and away to indicate continuing driving was more effective than the opposite combination. Furthermore, the turn indicator was regarded as intuitive for signalling that the AV will yield. Practitioner Summary: Future automated vehicles (AVs) may have to communicate with vulnerable road users. Many researchers have explored explicit communication via text messages and led strips on the outside of the AV. The present study examines the viability of implicit communication via the lateral movement of the AV.