Characterizing urban road CO2 emissions: A study based on GPS data from heavy diesel trucks

The determination of carbon dioxide (CO ₂ ) emissions from heavy-duty diesel trucks (HDTs) is important for the development of traffic emission reduction strategies. This study quantified the CO ₂ emissions from 5,996 HDTs on different road types using a bottom-up approach combined with the application of the International Vehicle Emissions (IVE) model based on 1.24 million trajectory points. A correlation analysis was conducted on the hourly traffic flow, driving mileage, speed, and CO ₂ emissions of HDTs in the urban area of Kunming, China. The traditional emission intensity allocation method was improved by establishing a high-resolution (1 × 1 km) emission inventory using trajectory points and the road network density. The results indicated that higher driving speeds can reduce CO ₂ emissions, but HDTs typically maintain speeds of 40–60 km/h, with emission coefficients around 500 kg/km; HDTs complying with China III standards are significant contributors to CO ₂ emissions; Regional CO ₂ emissions from HDTs are highly influenced by traffic flow and driving distances; Vehicle restriction policies contribute to increased nighttime emissions; A pollution spatial allocation method based on trajectory point density and road network density better reflects the regional spatial distribution of CO ₂ emissions from HDTs; CO ₂ spatial distribution is predominantly concentrated in the southeast of urban areas, primarily influenced by urban industrial layout.