2022 Volume 2022 Issue 1 Pages 47-53
From the viewpoint of improving reliability and availability, three requirements for SPaT (Signal Phase and Timing) information for automated driving were identified: (1) the error between SPaT information and actual light color should be less than ±300ms, (2) errors in SPaT information should be detected and the vehicle should be notified of the errors, and (3) the provision of SPaT information in various signal control systems should be achieved. First, for the V2I system, the technical specifications for SPaT information provision infrastructure using V2I were decided on by FY2020. Next, from the viewpoint of reducing maintenance costs, etc., we started studying the V2N system using mobile lines in FY2019, and by FY2021, through FOTs (Field Operational Tests) in Saitama Prefecture, we worked on the establishment of SPaT information provision technology using the V2N method. We also studied the social functional requirements of the SPaT Information Center, which constitutes the core of the social implementation model envisioned in the study of the V2N method. Based on these studies, in FY2022, we conducted FOTs integrating a series of components from SPaTs at 17 locations to simulated on-board devices, and verified the effectiveness of the three SPaT information provision methods and of the overall system configuration.
