Work

Rising carbon emissions from expanding highway tunnels and reduction pathways in China

Year: 2025

Type: article

Abstract: Highway tunnels are expanding rapidly in China, driving rising operational carbon emissions, yet systematic assessment methods remain limited. Here, we develop a provincial-scale carbon intensity model using empirical data from Sichuan Province, integrating regional electricity emission factors and geological characteristics. The model estimated emission intensities across 30 provinces, yielding a national average of 16,805 tCO 2 -eq per km, and validation against 88 tunnel cases from five provinces shows prediction error of less than 5%. We further propose a low-carbon cross-section design strategy and evaluate three policy-technology interaction scenarios: baseline, high-reduction, and low-reduction. The high-reduction scenario could lower emissions by more than 18% relative to the baseline, whereas the low-reduction scenario leads to limited effectiveness. Establishing a nation-wide tunnel emission model is essential for infrastructure planning, policy design, and accelerating low-carbon transitions in China and other rapidly developing economies.

Source: npj Sustainable Mobility and Transport

DOI: 10.1038/s44333-025-00063-3