Including maintenance in life cycle assessment of road and rail infrastructure-a literature review

Purpose LCA is increasingly used in infrastructure policy and planning. This study maps approaches used in comparative LCA of road and rail infrastructure to (1) determine the length of the analysis period, (2) estimate the maintenance frequency, and (3) include the effects of climate change on infrastructure performance. A LCA may need to fulfil different requirements in different decision-contexts. The relevance of the approaches for decision-making in policy and procurement is therefore discussed. Methods Ninety-two comparative LCAs of road and rail infrastructure published in peer-reviewed journals January 2016-July 2020 were reviewed. Papers were found through a systematic process of searching electronic databases, applying inclusion criteria, and conducting backward and forward snowballing. Results and discussion The analysis period was commonly determined based on infrastructure service life. The maintenance frequency was estimated based on current practice, laboratory tests, modelling, or scenarios. The effects of climate change were considered in two papers by comparing results in a control case and in a changed climate. In policy and procurement, current practice approaches are not adapted to innovative solutions or to climate change. Modelling and laboratory tests could improve calculations of the maintenance phase but might have some limitations related to innovative solutions. Scenarios could be readily applied in a policy context; however, in procurement, consistent and generic scenarios should be used. Conclusions Results suggest what approaches could be used to account for maintenance in infrastructure LCA depending on the decision-context. The LCA community is suggested to research other approaches than current practice to account for long analysis periods, climate change, and innovative solutions. Additionally, literature not covered here could be reviewed for additional approaches and perspectives. Examples include stand-alone LCAs, method development papers, papers on the individual approaches and decision-contexts, certification systems, standards, and guidelines.