Strategy of indicator incorporation for roadway sustainability certification

Over the last decade, various rating systems and indicators have been proposed for evaluating or certifying roadway sustainability. However, there is no systematic method for the roadway projects to adopt the indicators of the rating systems to enhance sustainability for certification. This study developed a strategy for adopting indicators in a roadway rating system for sustainability certification. First, the framework and rules for prioritizing the indicators were established from literature review. Then, carbon emissions, costs, and the difficulties of employing the indicators were analyzed in a roadway case study. Finally, the priorities for adopting the indicators were determined. The results revealed that the indicators with higher score–unit ratios should have higher priorities in the project. By using the developed framework, the simultaneous analysis of multiple dimensions enables appropriate investigation into roadway sustainability problems. The score–unit ratio is a simple but effective metric to evaluate whether a project has incorporated appropriate indicators to enhance sustainability.