Stochastic Network-Level Pavement Life Cycle Assessment Framework Development

Abstract: Project-level life cycle assessments (PLCA) are crucial for detailed project-specific decisions, but they may not fully capture the environmental impacts of an entire road network. Network-Level LCA (NLCA) complements PLCA by providing a broader, strategic view, enabling more informed decision-making at the network level. Given its network-wide application, NLCA goals must be aligned with the objectives and requirements set forth by state or federal authorities for infrastructure projects. This study introduces a framework for NLCA that would ensure consistency in methodologies across the agency’s pavement network. The framework encompasses methodological approaches and the ability to be integrated into Pavement Management Systems (PMS), use of bottom-up versus top-down analysis, and utilizes deterministic versus probabilistic modeling. By ensuring compatibility with PMS, transportation agencies can couple environmental impacts along with current PMS performance objectives, such as economics, user level of service, and safety, into the decision-making process. The bottom-up approach allows agencies to first implement environmental product declarations (EPDs) and take advantage of advancements in PLCA. Furthermore, probabilistic modeling offers significant advantages in NLCA, providing agencies with a clearer understanding of the uncertainty involved in maintenance or rehabilitation strategies, enhancing sensitivity analysis to identify the most influential inputs and improve result precision, thereby enabling more robust decision-making at the network level. While NLCA provides a broader scope of analysis, it introduces several challenges at various stages of the life cycle assessment. The complexity of managing multiple pavement sections, varying construction years, distinct performance periods, and varying jurisdictions are challenging issues. Hence, some LCA assumptions and the LCA system boundaries must be adjusted to account for these challenges. To demonstrate the use of the NLCA methodology, a case study using the Arizona pavement network was conducted.