We develop a queuing-theoretical model for mixed-gender public toilet systems, incorporating
contemporary Equity, Diversity, and Inclusion (EDI) principles. The model uses a multi-server Markovian
framework with gender-mixed arrival streams, incorporating user discomfort and strategic behavior such
as balking and reneging. We introduce the Flush Equity Index (FEI), a novel fairness metric designed to
evaluate equity in access across gender and identity groups. Our analysis reveals paradoxes inherent in
socially progressive restroom designs: while increased equality of access aims to reduce inequities, it may
unintentionally decrease system efficiency and user satisfaction. To address this, we propose several policy
interventions, including the Privacy-Aware Stall Assignment Protocol (PASAP), behavioral nudges, and a
blockchain-based ToiletCoin system. The ToiletCoin system optimizes queue allocation by rewarding users
for cooperative behavior, such as nudging and prioritizing high-urgency users, while reducing discomfort.
Finally, we recommend using the FEI in restroom equity audits to guide design and policy decisions.
