On the user-based assessments of virtual reality for public safety training in urban open spaces depending on immersion levels

• A workflow for testing VR multi-risk training in urban built environment is proposed. • Knowledge and user experience in immersive and non-immersive VR-SG are compared. • Recommendation for enhanced realism, active role of crowd and easier use are drawn. • Future developments on target groups, content analysis and social gaming are outlined. The increasing use of VR (Virtual Reality) training tools in safety-related fields has prompted the scientific community to explore methods for assessing their effectiveness across different levels of immersion. While numerous studies have been conducted in sectors such as healthcare, transportation, agriculture, aviation, mining, firefighting, and construction, one area that remains underexplored is risk training for general public against natural and man-made disasters in both indoor and outdoor built environments. In this context, the paper aims at validating a prototype for VR multi-risk (heat wave and earthquake) training in urban open spaces that was developed according to a Serious Game (SG) approach. To address insights on its extensive adoption, the VR-SG was tested for comparison of three modes: traditional by video recording, non-immersive by desktop, immersive by headset. Outputs from feedback questionnaires on knowledge gain and transfer to expansive contexts, as well as on user experience, suggest that the effectiveness of knowledge acquisition differs significantly between headset and video, as well as between desktop and video, but shows no significant difference between headset and desktop. Additionally, while headset outperforms desktop in terms of engagement, perceived usefulness, and realism, it falls behind in ease of use. Finally, further analyses on training outcome by age, contents of open-ended answers, in-game errors and administration procedures supported the discussion of key aspects in targeting VR for public safety communication.