A mixed-ordered Logit approach to investigate correlations among different affordances in fire evacuation

The evaluation of the effectiveness of safety installations (such as emergency exits, lighting, etc.) is a key factor to improve the evacuation performance of buildings or transportation systems. In fact, even though an installation is designed to achieve a given design goal, it could happen it does not perform as intended. According to the Theory of Affordances, this could be interpreted in relation to different affordances, namely it cannot be (1) sensed (i.e. Sensory Affordance), (2) understood (i.e. Cognitive Affordance), (3) physically used (i.e. Physical Affordance), or (4) it does not fulfil its intended goal (i.e. Functional Affordance). This study investigates how this issue can be addressed
combining the Theory of Affordances and the Random Utility Theory. This work shows that ordered choice models are powerful tools to investigate the relations among affordances. In this work, an ordered choice model is estimated using data from a Virtual Reality experiment aimed at investigating the design of flashing lights at emergency exit portals for road tunnel evacuation. The proposed model demonstrates that both Sensory and Cognitive Affordances statistically affect Functional Affordance. The results demonstrate also how participant demographics and installation variables affect Functional Affordance.