Rethinking environmental LCA life stages for transport infrastructure to facilitate holistic assessment

Life cycle assessment (LCA) aims to provide a near full accounting of impacts from the complete life of a product, to avoid burden shifting between different parts of the life cycle. However, this is exceptionally difficult with transport infrastructure because important parts of their impact lie outside the widely applied industrial-product-oriented LCA life stages: production, manufacturing, use, and end of life. To account for those missing impacts, we propose a new framework for assessing the life cycle impacts of transport infrastructure. This framework takes account of the differences between transport infrastructure and the industrial product system to which LCA is most attuned. First, rather than a linear process from material extraction to disposal, this LCA framework accommodates the multiple iterations of transport infrastructure through circular life stages. These reflect the long lifetimes, durability, persistence, and feedback loops of transport infrastructure. Second, this framework recognizes the impact at the start of the life cycle created by demolition of previous infrastructure or land clearing. Third, the tightly linked external impacts that transport infrastructure induces, including influences on travel behavior, local land use, land use, land use change and forestry, and network effects are captured. Fourth, this framework recharacterizes end of life as partial end of life, in reflection of the widespread reconstruction, major refurbishment of and persistence of indirect impacts from transport infrastructure.