Sustainable transportation infrastructure: comparative analysis and a comprehensive decision-support tool

Purpose There are two critical gaps in the existing knowledge: a measurable set of sustainability metrics and a comprehensive decision support tool for evaluating transportation projects. This study aims to address these gaps. Design/methodology/approach Transportation sustainability factors were identified and used to develop a survey administered to a purposive sample of 50 transportation experts from Asia, the United States (US), Europe, and Africa. Survey responses were analyzed using the Fuzzy Analytic Hierarchy Process (AHP) to estimate metric- and factor-level weights from global, US, and non-US perspectives. These weights were then implemented to construct a Sustainability-driven Prioritization Index (SPI), which was developed based on global stakeholder input to ensure worldwide applicability. The SPI was subsequently validated through a case study in states bordering the Gulf of Mexico. Findings The findings show that globally, livable public spaces and amenities, transportation costs, and active citizen involvement in transportation planning were found to be the most important factors for environment, economy, and society, respectively, while road fatality intensity and integrated plan of all significant impacts led in operation and safety. This approach was among the first to combine stakeholder feedback and global adaptability for assessing and ranking transportation project sustainability. Originality/value The SPI is a quantitative scoring tool that assigns weighted values to 55 sustainability factors across five metrics. Transportation planners input project-specific data, and the tool could calculate a comprehensive sustainability score using stakeholder-informed weights. This enables objective comparison and ranking of multiple transportation projects, helping policymakers prioritize investments that maximize sustainability outcomes.