Spatial and operational interventions for healthy cruise ship design using agent-based modelling

• Simulated passenger movement on cruise ships using agent-based modelling under different design and operational scenarios. • Collision rate used as a proxy for close-contact exposure and potential transmission risk. • High occupancy density and compact layouts significantly increased collision frequency. • Access restrictions can help alleviate crowding, but the effectiveness depends on where the restriction zone is placed. • Spatial configuration can act as a non-pharmaceutical, passive prevention mechanism for infectious disease spread. Cruise ship environments have been identified as high-risk settings for communicable disease outbreaks. The severe COVID-19 outbreaks aboard several cruise ships have further intensified concerns about transmission in these confined, densely populated environments. Although some behavioural interventions have been studied, the influence of spatial and operational design on transmission risk remains under explored. To address this gap, this study applies agent-based modelling (ABM) to simulate passenger movement patterns on mixed-use cruise ship decks as a surrogate for infection transmission. By modelling individual movement behaviours and collisions (close-contact exposure) within the mixed-use decks, the ABM approach supports the development of spatial design and operational strategies that can reduce transmission risk and improve the efficiency and healthiness of onboard circulation. We conducted verification and parametric tests to assess model performance and designed three experiments to evaluate the effects of varying occupancy levels, infection prevalence, spatial layouts and access restriction strategies with 1181 simulation runs, the simulation results are complemented by spatial analyses of deck plans to inform evidence-based recommendations for safer cruise ship environments. We identified three key spatial drivers of disease transmission risk on cruise ships. First, higher occupancy density and compact layouts significantly increased close-contact events, as passengers navigated narrow, poorly connected corridors. Second, the effectiveness of quarantine interventions depended not just on their presence but on their spatial placement: centrally located restrictions amplified congestion, while peripheral placement helped alleviate it. Third, simple passive design changes—such as widening corridors or enhancing internal connectivity—reduced movement bottlenecks and collisions, without requiring behavioural adaptation. Together, these findings demonstrate that spatial configuration is not merely a backdrop but a powerful determinant of health resilience in high-occupancy environments.