Consideration of life cycle energy use and greenhouse gas emissions for improved road infrastructure planning

Abstract: Global warming is one of the biggest challenges of our society. The road transport sector is responsible for a big share of Greenhouse Gas (GHG) emissions, which are considered to be the dominant cause of global warming. Although most of those emissions are associated with traffic operation, road infrastructure should not be ignored, as it involves high consumption of energy and materials during a long lifetime.The aim of my research was to contribute to improved road infrastructure planning by developing methods and models to include a life cycle perspective. In order to reach the aim, GHG emissions and energy use at different life cycle stages of road infrastructure were assessed in three case studies using Life Cycle Assessment (LCA). These case studies were also used for development of methodology for LCA of road infrastructure. I have also investigated the coupling of LCA with Geographic Information Systems (GIS) and the possibility to integrate LCA into Environmental Impact Assessment (EIA) and Strategic Environmental Assessment (SEA).The results of the first case study indicated that operation of the tunnel (mainly, lighting and ventilation) has the largest contribution in terms of energy use and GHG emissions throughout its life cycle. The second case study identified the main hotspots and compared two methods for asphalt recycling and asphalt reuse. The results of the third case study indicated that due to the dominant contribution of traffic to the total impact of the road transport system, the difference in road length plays a major role in choice of road alternatives during early planning of road infrastructure. However, infrastructure should not be neglected, especially in the case of similar lengths of road alternatives, for roads with low volumes of traffic or when they include bridges or tunnels.This thesis contributed in terms of foreground and background data collection for further LCA studies of road infrastructure. Preliminary Bill of Quantities (BOQ) was identified and used as a source for site-specific data collection. A new approach was developed and tested for using geological data in a GIS environment as a data source on earthworks for LCA. Moreover, this thesis demonstrated three possible ways for integrating LCA in early stages of road infrastructure planning.