Assessment of Carbon Emissions in the Construction Stage of Project-Level Highways

Based on the theory of inventory analysis and the emissions factor approach, we collected the carbon emissions factors and proposed a measurement method and evaluation indicator for carbon emissions in the construction stage of project-level highways. The carbon emissions of a secondary highway project in construction stage were calculated, and the composition of carbon emissions and carbon intensity in the construction stage were analyzed from two perspectives. According to the calculation results of the instance project: (1) the construction period of pavement projects has the largest proportion of carbon emissions; (2) the construction stage carbon emissions intensity per unit of pavement area of bridge and tunnel sections is 6.1 times and 5.4 times that of roadbed sections, respectively; and (3) carbon emissions per thousand yuan investment are 131 kg CO₂e. Low-carbon-emissions road construction should start with the selection of low-carbon road construction materials and reasonable control of the bridge-tunnel ratio.