A project-level infrastructure management framework for sustainable roadways

Over the past two decades, roadway infrastructure in the United States has experienced severe deterioration, costing road users billions of dollars in wasted fuels, lost time, and higher numbers of accidents. Transportation infrastructure asset management initiatives, which aim at providing and maintaining physical infrastructure assets at an acceptable level, need to address various economic, social, and environmental issues. Therefore, the American Association of State Highway and Transportation Officials (AASHTO) has encouraged public agencies to incorporate sustainable development principles into their decision-making and organizational operations at a program level. Meanwhile, at a project level, maintenance, repair, and rehabilitation (MRR) projects for roadway infrastructure are still mostly undertaken by traditional techniques, resulting in higher overall life cycle impacts. The use of non-traditional techniques including accelerated methods is expected to reduce the overall impacts; however there is a lack of infrastructure management frameworks that support public agencies’ decision-making procedures in justifying the use of non-traditional techniques. Therefore, the goal of this research is to develop a project-level infrastructure management framework to consider multiple factors in decision-making and to analyze the life cycle economic, social, and environmental impacts of traditional and non-traditional (including accelerated methods) roadway MRR techniques. The proposed framework utilizes decision flowcharts and multi-criteria decision-making (MCDM) methods to shortlist alternatives that meet project requirements to facilitate preliminary decision-making. And then, this framework applies life cycle assessment (LCA) and life cycle cost analysis (LCCA) to quantify the life cycle impacts of candidate project alternatives following the triple bottom line of sustainability. MRR techniques analyzed by the framework include hot mix asphalt (HMA) and warm mix asphalt (WMA) overlay, hot-in-place recycling (HIPR), cold-in-place recycling (CIR), full depth reclamation (FDR), intelligent compaction (IC), and use of precast concrete pavement systems (PCPS). The decision flowcharts and MCDM model in the proposed framework are developed based on existing literature and the results of a survey of state departments of transportation in the United States. Analytical hierarchy process (AHP) and analytical network process (ANP) are used to determine the weights of criteria for the MCDM model, and a customizable decision support tool is created in a spreadsheet program to facilitate application of the model. For the LCA-LCCA model, the overall life cycle impacts include: i) agency costs and environmental impacts, ii) user costs and environmental impacts due to lost time and wasted fuel, and iii) user costs due to increased crash events. Software programs and databases including Athena Pavement LCA, GREET®, MOVES, and other miscellaneous data sources are used for LCA; while survey results, RSMeans 2016, and other miscellaneous cost sources are used for LCCA. The LCA-LCCA model is also capable of performing what-if analysis by adjusting variables. Thus, the model allows public agencies to apply their own data and priorities based on their sustainability goals, objectives, and performance measures to obtain relevant results. The proposed framework is illustrated through case studies and validated by expert opinion and literature contrasts. Future studies may expand this framework to include more factors in the MCDM model and additional impact items in the LCA-LCCA model.