Evaluating All-Age-Friendly Community Environments with Cross-Generational Interaction Potential: A Multi-Objective Assessment Based on Cases from China and Italy

Communities worldwide are increasingly required to support populations spanning multiple generations while maintaining social cohesion in the context of rapid demographic ageing and urban transformation. Although frameworks for age-friendly or inclusive environments have gained international traction, existing evaluation methods seldom integrate the environmental qualities necessary for all-age-friendliness with the spatial and social conditions that enable cross-generational interaction. This study addresses this gap by developing a dual-lens evaluation framework that quantifies both fundamental environmental attributes and the interaction potential embedded within community spaces. Grounded in field investigations, spatial analysis, expert consultation, and user surveys, the study establishes a hierarchical indicator system comprising nineteen prerequisite indicators and sixteen enhancement indicators across five dimensions: site accessibility, spatial integration, environmental comfort, safety and health, and participation and inclusion. To operationalize the framework, a combined Fuzzy Analytic Hierarchy Process and multi-objective optimization model was employed, enabling the representation of interdependencies between essential conditions and value-enhancing features. Application of the framework to 24 community cases in Shanghai and Florence reveals both shared structural patterns and distinctive cultural influences: Shanghai demonstrates strengths in walkability and health-supportive infrastructure, whereas Florence excels in natural contact and environmentally integrated spatial typologies. The findings underscore the necessity of balanced environmental performance for achieving high-quality, all-age-friendly community spaces with strong cross-generational engagement potential. The proposed framework provides a replicable and analytically rigorous tool for environmental and social impact assessment, offering guidance for planners, policymakers, and designers seeking to promote inclusive, resilient, and socially cohesive community environments.