Almost 25% of the environmental pollution, measured by the indicator of global greenhouse emissions, is emitted by transport. Changes in the mobility behavior of the population will be essential if the 17 UN Sustainable Development Goals (SDGs) and the goals of the EU Commission’s Green Deal are to be attained. Accordingly, the existing infrastructure has to transform into a sustainable transport infrastructure through further optimizations in the future. Therefore, continuous optimizations and improvements of designs, materials, and processes are crucial to achieving long-term sustainability. This study investigates different superstructures with the method of life cycle assessment using the example of the emerging high-performance infrastructure at the Brenner Base Tunnel (BBT). The study analyzes all relevant life cycle stages (A1–C4) and validates different effects of service lifetimes of superstructure elements on the open track and in the tunnel. The results, which are presented in the form of GWP, AP, and NRCED, show that there is environmental reduction potential, especially in the stage of use. As more frequent modernization cycles and the associated remanufacturing of superstructure elements account for a significant proportion of the total environmental impact, lifetime extending optimization of products yields improvements in the ecological footprint.

Traffic contributes nearly 25% of global greenhouse gas emissions. For designing new traffic routes and decision-making processes, it is essential to incorporate integral life cycle assessments (LCAs) to ensure sustainable solutions and to achieve the UN Sustainable Development Goals (SDGs). This study compares two fictitious routes: a typical Austrian mountain pass road (Route A) with a 3% gradient and a new route (Route B) featuring a 1000 m tunnel, reducing distance and inclines. The LCA analyzes Route B’s lifecycle, from material supply to 100-year tunnel usage, comparing it against a traffic LCA of Route A’s operational emissions. The tunnel assessment considers the New Austrian Tunneling Method, local materials, and typical geology. Traffic effects are analyzed using Austrian vehicle stock data, following EN 17472 and EN 15804 standards. The results, based on Global Warming Potential, indicate that Route B’s construction, maintenance, and utilization generate lower environmental impacts than Route A’s traffic emissions. The tunnel offers overall environmental savings, with its construction and maintenance impacts offset within approximately 10 years. Traffic usage is identified as the primary long-term emission source. This research highlights the significance of integral LCAs in creating a sustainable built environment and supporting a decision-making process in transport infrastructure construction.

Previous studies of road or railway infrastructures have shown that traffic emissions outweigh the environmental impacts of the product stage and construction stage over the entire life cycle. Traffic usage is therefore the main emitter over the life cycle (A1–C4). Due to the small number of sustainability assessment systems, the question of how to consider traffic emissions in detail in an integral life cycle assessment has arisen. This study examines Austrian car traffic and investigates environmental impacts beyond the scope of carbon dioxide and particulate matter. The results were determined for a selection of common impact indicators. In addition to driving in flat terrain, an approach is presented that enables the evaluation of emissions due uphill and downhill driving. Thus, route options and route closures/detours due to maintenance work can be evaluated in a simple way. During the analyses, a traffic calculator was developed, which can currently assess different cars depending on the route specifics (flat/hill). The tool can be expanded to include other road vehicles (buses, trucks, motorcycles) and trains as well. This will simplify evaluations and decision-making processes and provide optimal support for a future-proof sustainable built environment.

Sustainability challenges increasingly forces stakeholders in the construction industry to meet the United Nations Sustainable Development Goals (SDGs) and to promote long-term sustainable building practices. Life Cycle Assessment (LCA) has become a well-established method for assessing sustainability and numerous tools have been developed for evaluating buildings. However, for infrastructure projects, particularly in mechanized tunnelling, the limited availability of assessment tools makes sustainability evaluations highly complex. This study, therefore, focuses on the LCA of mechanized tunnelling for transport infrastructures and presents a LCA tool designed to simplify the analysis process. The Excel-based tool was developed in collaboration with tunnelling experts to evaluate excavation processes for four types of tunnel boring machines (TBMs) – Single Shield, Double Shield, EPB Shield, and Mixshield – under varied geological conditions and tunnel dimensions. Considering the complexity of tunnel excavation, including geotechnical uncertainties and logistical aspects, the tool uses averaged parameters for energy consumption, logistics and maintenance. This enables reliable and accurate environmental impact assessments for typical traffic tunnels, including subway, railway and highway tunnels, in accordance with EN 17472 standards. The user can thus perform an LCA of the tunnel excavation by inputting a limited set of parameters including machine type, geological conditions (e.g. hard rock or soft ground), tunnel diameter and tunnel length. Results are presented for the global warming potential and ten additional environmental impact indicators in line with EN 15804. This research, along with the developed LCA tool, aims to streamline future LCAs and enhance sustainability assessments for tunnel construction. Integrating this tool into comprehensive integral LCAs offers valuable support for decision-making processes, such as route selection, and for evaluating the environmental impact of mechanized tunnelling activities.