By 2045, Sweden is to have zero net emissions of greenhouse gases, implying that also the transport sector must reduce its emissions to nearly zero by that year. Planning for emission reduction measures require network level studies showing environmental impacts of the transport network. Previous studies do not allow assessment of current hotspots in the infrastructure network, which limits their relevance for decision-support in this question. The aim of this paper is to assess the current annual climate impact and primary energy use of Swedish transport infrastructure by using a methodological approach based on life cycle assessment. The scope includes new construction and management of roads, railways, airports, ports, and fairway channels. The climate impact was estimated to 3 million tonnes carbon dioxide equivalents and the primary energy use was estimated to 27 terawatt hours. Mainly road and rail infrastructure contributed to these impacts. The environmental hotspots in the infrastructure network were identified as management of the infrastructure stock (particularly reinvestment of road and rail infrastructure) and material production (particularly production of asphalt, steel, and concrete). Planners should work systematically with emission and energy efficiency in these areas to reduce impacts of Swedish transport infrastructure. Additional research on impacts of small construction measures, the size of biogenic carbon emissions (in standing biomass as well as soil carbon), and the use and impacts of asphalt used in road construction and management would further increase the understanding of Swedish transport infrastructure at the network level.

The possibilities to influence environmental impacts during the road life cycle are greatest in early planning; however, the lack of project specific data makes it difficult to use life cycle assessment as decision-support. This paper examines how life cycle assessment can be used to support the choice of road corridor, considering the practical prerequisit of simplicity and usefulness of results for decision-making. The model LICCER was used to quantify life cycle impacts of road corridors in a construction project in Sweden. Availability of input data and usefulness of results was discussed with road authorities in Sweden, Norway, and Denmark. Traffic operation contributed most to life cycle impacts in all road corridors, thus the shortest construction alternative had the lowest life cycle impacts. However, the shortest alternative had the highest infrastructure related impacts due to large quantities of earthworks. Parameters that had the highest influence on results were those that affected the impacts of traffic, earthworks, and pavement. While workshop participants agreed that project specific data are scarce and uncertain in early planning, they also believed that planners can make satisfactory estimations and that the model output is useful to support the choice of road corridor. To balance simplicity and usefulness of results, data collection should focus on parameters that have high contribution to environmental impacts, that differentiate the road corridors, and are not proportional to the road length. To implement life cycle assessment in practice, models should preferably include nation specific data approved by the national road authority.