Carbon accounting for transport infrastructure: The relevance of non-traffic emissions

To achieve climate neutrality by 2050, it is crucial to decarbonize the entire road transport sector. Borrowing from the energy sector, this contribution presents a novel well-to-wheel (WTW) approach to assessing the carbon footprint of historical and long-standing motorway infrastructure, integrating traffic (ET) and non-traffic (ENT) emissions during the use phase. This method has been applied to the Brenner Motorway in northern Italy. The results show that ENT accounted for approximately 1% of total WTW emissions in 2023. Scenario analysis for the year 2040, supported by Monte Carlo Simulations, confirms the dominance of ET under varying policy, technological, and demand conditions. However, the potential for ENT to increase in relative importance in the future is also recognized. The findings emphasize that decarbonizing the vehicle fleet remains the primary policy focus. However, incorporating ENT is also essential for carrying out comprehensive carbon assessments to achieve net-zero transport infrastructure.