Development of Scenario-Based Approach Aided by Key PSFs to Design of New Interface of Autonomous Vehicles Monitoring System: A Case Study
Authors: Aoki Hirotaka , Kobayashi Nozomi , Fuke Mizuki , Yasui Tomonori 
Published: June 2023

In the present paper, we develop an improved scenario-based design approach to design a new interface of the monitoring system for autonomous vehicles that adapts to the autonomous driving levels 4 to 5 condition. Although the future society with high-level autonomous vehicles such as those having levels 4 to 5 is clearly anticipated, there still remains much uncertainty relating to how autonomous vehicles are implemented in terms of platform technology (e.g., AI, image processing, etc.), social norms (e.g., laws, safety responsibility, etc.), context of use (e.g., human role, allocated tasks, etc.) and so forth. For example, it is unclear the followings: What can be done automatically by the platform technologies of autonomous vehicles (i.e., uncertainty in technological advancement), what kind of socio-technical support can be given when human operators have to intervene in a critical incident that cannot be managed automatically (i.e., uncertainty in tasks required to human), etc. Caused by these uncertainties, it is of great difficulty to design user-centered interface of autonomous vehicle control/monitoring systems since the users/operators’ tasks and needs are not well defined.The paper proposes a design approach adapting to the above-mentioned background issues. The most part of the approach is based on scenario-based design (Rosson and Carroll 2002). This is referred to as the technique to elicit effective specifications of interface based on scenarios in which how a human uses and interacts with a specific system are vividly described to capture the essence of interaction and physical design. In the approach, requirements/rough draft of basic specifications are elicited by interpreting desirable interaction/behavior described in the scenarios Although the scenario-based design is applicable for a new product design, creating successful scenario having appropriate level of details and in which key behaviors/tasks and their contexts are covered requires rich knowledge about interaction design as well as expertise/experiences in practice. In order to support the difficulty in creating scenarios, we propose a series of processes where scenarios are created and refined iteratively supported by a list of PSFs (performance shaping factors) directly connected with the system’s context of use. The list of PSFs are, in our processes, used as guidelines/heuristics not only to obtain insight for creating narrative description of a human, but also to keep consistency of envisioned usage episodes in scenarios (refined iteratively) by maintaining an orientation to identical key context factors. A case study was performed with a big manufacturing company in Japan where our design approach was applied to design a new interface of autonomous vehicles monitoring system. The potential target users of the system are operators working at a general operation center of public transportation in high-level autonomous vehicles condition. In the beginning of the design phase, the first version of scenario where sequences of possible and desirable operators’ behaviors were stressed was created by referring PSFs in driving contexts. By interpreting potential needs and decomposing them into requirements logically, the first version of design solution was developed. Along with both of iterative revisions of scenarios and subsequent design improvements, interface design was refined. Based on the results of this application and feedbacks from our collaborating company, we discuss feasibility of our approach as well as implications for development of systems for autonomous vehicle monitoring.