Fig. 4: Regional analysis of highway tunnel carbon emission characteristics in China.
From: Rising carbon emissions from expanding highway tunnels and reduction pathways in China
a Provincial capacity rating based on highway tunnel carbon emission intensity. b Provincial capacity rating based on total carbon emissions from highway tunnels (Level 4 to 1 indicates increasing capacity). c Comprehensive rating of tunnel carbon emission intensity and total emissions, where the “Low-Low” mode indicates that the province ranks in the bottom 50% nationally for both carbon emission intensity and total carbon emissions.
