Examining Sustainability Factors in US Transportation Systems Using the RII Method

Transportation in the United States (US) plays a crucial role in facilitating economic activities by connecting producers with consumers and enabling the movement of goods and services. Additionally, it contributes to social integration by providing mobility and access to employment, education, and leisure activities across the country. However, its impact on various facets of the US, such as the environment, has been significantly destructive. Mitigating these negative effects and ensuring long-term efficiency require advancing sustainability within transportation systems. Over the last two decades, there has been increasing attention from researchers towards building sustainable transportation systems. However, there remains a need for a deeper understanding of the factors influencing sustainability across different perspectives and their respective impacts. This study aimed to identify a comprehensive list of factors affecting the sustainability of transportation systems across three critical dimensions: environment, economy, and society. These factors were subsequently ranked based on their impacts. A thorough literature review provided insights into the factors contributing to environmental, societal, and economic sustainability of transportation. A structured survey was designed and distributed among professionals working at different national transportation agencies, resulting in 50 completed responses. The Relative Importance Index (RII) method was employed to determine the overall ranking of factors. The category-based results were also presented and analyzed. The outcomes of this study will assist decision-makers and project managers in making informed decisions regarding resource allocation, thereby leading to improved sustainability of transportation systems from environmental, societal, and economic perspectives.