In recent years, automobiles have introduced various infotainment systems for drivers and passengers, providing a high-tech interactive space. While the focus has been on head-up display (HUD)-oriented services for the driver, advances in autonomous driving technology are increasingly driving research into improving the experience for non-driver passengers. However, HUD systems for passengers are limited, and few studies have empirically evaluated their effectiveness or preferences. In this paper, we propose a novel infotainment system for passengers in moving vehicles, the Full-window Augmented Reality System (FARS), and empirically verify its impact on passengers' spatial perception and riding experience. The FARS is implemented in a real vehicle using a short-throw projector and a transparent AR film to create an AR display on the entire right window of the passenger seat. To explore the impact of FARS on users' spatial knowledge and preferences, we further conducted a user study comparing the difference between FARS and the Seat Back Display (SBD), commonly used in passenger mobility services. The results suggest that the FARS is a valuable infotainment system for passengers and has advantages in memorizing the features or locations of specific environments outside the vehicle while enhancing the user's travel experience.
