A Novel Approach to Estimating Greenhouse Gas Emissions from Federal Highway Construction Projects in Brazil

In Brazil, the maintenance and expansion of the federal road network conflict with the country’s climate neutrality goals. The National Department of Transportation Infrastructure (DNIT), responsible for Brazil’s federal highways, lacks tools to assess and mitigate greenhouse gas (GHG) emissions from its projects, which can be achieved through the life cycle assessment (LCA) methodology. Additionally, the scarcity and insufficient quality of environmental data on Brazilian road materials led to using foreign databases in LCA studies conducted in Brazil, generating uncertainties in the results. This research aims to apply LCA to analyze the GHG emissions from highway projects developed by DNIT. The analysis covers the phases of material production, transportation, and construction. Additionally, this study investigates the influence of the leading project disciplines on the results and the differences in outcomes resulting from the use of local Portland cement compared to its equivalent produced in the United States of America (USA) and Europe. The results indicate that the materials production phase has the most significant impact on the project’s global emissions, contributing over 78% in all scenarios. The transportation phase accounts for more than 16% of global emissions, with the potential for greater contributions depending on project transportation distances. Environmental data showed that foreign cement increased the project’s global emissions by 7.31% (Europe) and 12.91% (USA), with the most significant differences observed in pavement disciplines. In all scenarios, the discipline of new pavement presented the highest unitary emissions, followed by the discipline of restored pavement, which showed average values 58% lower than the former, and earthworks. Other services, drainage, and special structures disciplines showed minimal influence on the results. In conclusion, this research proposes an approach to estimate the environmental impact of Brazilian federal highway projects, enabling early mitigation of GHG emissions during the design phase, focusing on critical disciplines and materials, and highlighting potential distortions associated with the use of environmental data from foreign cement in LCA studies of Brazilian highways. Finally, considerations are presented regarding improving and expanding the scope of the calculation methodology used in this study, allowing for a more comprehensive and accurate analysis of the environmental impacts associated with the Brazilian federal road network.