Implications of Human-Machine Interface for Inclusive Shared Autonomous Vehicles

Autonomous Vehicles (AVs), also known as self-driving cars, driverless cars, or robot cars, can perceive their environment and drive safely with little or no human inputs. Under the support of engineering, information science, anthropology, AVs have developed rapidly at the technical level, demonstrating to reduce human error operations and lessening road usage to save time. In the future, users will always be more released from driving tasks Self-driving vehicles can be more advantageous and feasible in public transportation than in private ones. Therefore, shared buses and logistics vehicles have been trial operation in various countries nowadays. Moreover, this technology will enable road traffic for people who cannot drive due to various physical and cognitive impairments. Therefore, inclusivity is often cited as one of the main reasons for promoting user acceptance of this technology, and it is fundamental in its application. Inclusive design can be achieved by identifying and addressing as many barriers to the Human-Machine Interface (HMI) as possible, focusing on human factors inside and outside the self-driving vehicle. It can enable groups with different needs to interact comfortably with the AVs and the traffic environment. Specifically, within a shared autonomous vehicle, we focus on transferring vehicle control between multiple users, reducing human error, and improving system availability. In addition, for many non-driving-related tasks (NDRT) derived from the gradual improvement of autonomous driving, the design of interactive devices and processes suitable for different groups and their cognition, the usability and comfort of the system will be improved, as well as the user experience. Concerning the scenes outside the vehicle, the impact of different types of external HMIs on the user experience of other user groups (e.g., young, old, cognitive, or physical disabilities, Etc.) attracted more attention from scholars. At the same time, communication channels and interfaces established between users and AVs will become more prominent on an inclusive basis. Consequently, HMI is essential for functional and inclusive driving automation, guaranteeing an efficient and satisfactory interaction between the automated system and different users.This paper provides an overview of the HMI challenges in shared driving automation from an inclusive design perspective, summarizing existing research on the role of HMIs in shared autonomous vehicles. The authors identified the fundamental changes in the way the user interacts with the car in shared autonomous vehicles using a systematic literature review including the following four steps: 1) identification of purposes and research questions of the literature review 2) definition of a literature search strategy by identifying a combination of sequential and iterative search queries; 3) analyze the retrieved articles compiling a concept matrix for each of them. As a result, relevant literature related to the research topic was selected; 4) identifying research gaps and inconsistent research results to make tacit domain meta-knowledge explicit. The paper will contain the analysis and discussion of the obtained data. Finally, the paper will discuss the future challenges for promoting a deeper exploration of inclusivity of HMIs for autonomous vehicles, also proposing the research avenues practical to increase the user's acceptance of this technology.