Human Factors Involved in Explainability of Autonomous Driving : Master’s Thesis

Abstract: Autonomous Car (AC) has been more common in recent years. Despite the rapid development of the driving part of the AC, researchers still need to improve the overall experience of the AC's passengers and boost their willingness to adopt the technology. When driving in an AC, passengers need to have a good situation awareness to feel more comfortable riding in an AC and have a higher trust towards the system. One of the options to improve the situation awareness is by giving passengers an explanation about the situation. This study investigates how the situational risk of specific driving scenarios and the availability of visual environment information for passengers will affect the type of explanation needed by the AC passenger. The study was conducted through a series of different scenario tests presented to online study participants and focused on the human interaction to level 4 and 5 AC. This study's primary goal is to understand the human-AC interactions further, thus improving the human experience while riding in an AC. The results show that visual information availability affects the type of explanation passengers need. When no visual information is available, passengers are more satisfied with the type that explain the cause of AC's action (causal explanation). When the visual information is available, passengers are more satisfied with the type that provide intentions behind the AC's certain actions (intentional explanation). Results also show that despite no significant differences in trust found between the groups, participants showed slightly higher trust in the AC that provided causal explanations in situations without visual information available. This study contributes to a better understanding of the explanation type passengers of AC need in the various situational degree of risk and visual information availability. By leveraging this, we can create a better experience for passengers in the AC and eventually boost the adoption of the AC on the road.