University of California Pavement Research Center

The California Department of Transportation (Caltrans) has a growing need to be able to quantify its greenhouse gas (GHG) emissions and the other environmental impacts of pavement operations, and to consider GHG and those other impacts in pavement management, conceptual design, design, materials selection, and construction project delivery decisions. Caltrans also needs to be able to evaluate the life cycle environmental impacts as part of policy and standards development. All these tasks can be performed using life cycle assessment (LCA), although there are different constraints and requirements with respect to the scope of the LCA and the data available for each of these different applications. The web-based software environmental Life Cycle Assessment for Pavements (eLCAP) is a project-level LCA tool that uses California- and Caltrans-specific life cycle inventories (LCIs) and processes. The LCI database has been critically reviewed by outside experts following ISO standards. eLCAP models the life cycle history of a pavement project by allowing a user to specify any number of construction-type events, occurring at a user-specified date, followed by an automatically generated Use Stage event that begins immediately afterward and lasts until the next construction-type event or the end-of-life date. The Use Stage models currently consider the effects of roughness in terms of International Roughness Index and use the same performance models that are used in the Caltrans pavement asset management system software, PaveM. eLCAP performs a formal mass-balancing procedure on a pavement LCA project model and then computes 18 different impact category values—including Global Warming Potential, Human Health Particulate Air, Acidification, and different forms of Primary Energy—and generates a detailed Excel report file to display graphs and tables of results. The results can be presented in terms of life cycle stage, material types, and other details.