Color in urban public spaces is often approached as an aesthetic issue, yet it also governs psychological responses, legibility and safety, place identity, and environmental performance. Despite three decades of research, planners and designers still lack measurable, audit-ready guidance that links color decisions to verifiable outcomes. This paper presents a systematic review that consolidates evidence from environmental psychology, architecture and urban design, cultural studies, and building and urban physics. Studies were screened for outdoor or outward-facing settings and for explicitly reported color variables and performance indicators. The findings are organized into four domains in which color operates as a system variable: psychological and physiological effects; cultural expression and place identity; functional zoning and wayfinding; and sustainability and environmental adaptation. Across these domains, the review identifies robust patterns—such as the central role of luminance and saturation in shaping affect, attention, and visibility—while highlighting where outcomes are strongly conditioned by cultural, climatic, and material context. On this basis, the paper proposes an Objective–Strategy–Metric–Validation (OSMV) framework that connects design objectives to color strategies, quantitative metrics (e.g., color difference, contrast, and reflectance measures), and procedures for simulation or field validation. Framed in this way, color emerges not as a decorative accessory but as a measurable design variable that can be integrated into performance-based planning, regulation, and multi-objective optimization of urban public spaces.
Cheng et al. (Thu,) studied this question.