Putting sustainability theory into roadway design practice: Implementation of LCA and LCCA analysis for pavement type selection in real world decision making

- A real world case study of pavement type selection for SR-836 extension project was conducted.
- Life cycle cost and environmental impacts of different pavement design alternatives were studied.
- Data collection and analysis were performed in close collaboration with Miami-Dade Expressway Authority.
- Results show flexible pavement has lower initial cost but higher long-term cost and environmental impacts.

Assessment of life cycle costs and environmental impacts of pavements has become an essential component of roadway design and asset management. The existing literature reveals that the economic and environmental sustainability of pavements depend on specific project characteristics. Hence, recent studies have called for real world case studies of pavement construction projects to better understand how the life cycle costs and environmental impacts of pavements vary based on different project characteristics. To this end, present study conducted comprehensive LCA and LCCA analyses to investigate the sustainability of different pavement alternatives for the SR 836-Southwest Extension Project in Miami, Florida. The study considered the agency costs and impacts as well as various use phase impacts and costs including those connected with pavement vehicle interaction and work zone traffic delays. In addition, the uncertainty related to the costs and impacts of construction and maintenance activities was assessed. The results indicated that at 90% confidence interval the flexible pavement design has lower cost and environmental impacts in the construction phase. However, when all phases are taken into consideration, the rigid pavement alternatives have lower environmental impacts and costs. The analysis also examined the sensitivity of the results to different parameters such as the discount rate and future traffic growth rate. The results of the sensitivity analysis indicated that the flexible pavement design has lower agency costs compared to rigid pavements at discount rates less than 4%. For discount rate values greater than 4.5%, the rigid pavement leads to lower life cycle costs.