Modeling carbon intensity of electric vehicles in the well-to-wheels phase under different traffic flow conditions

With the proliferation of electric vehicles (EVs), accurately assessing their well-to-wheels carbon intensity is crucial. In this study, a quadratic model was developed, integrating a top-down carbon accounting approach with field test data, to quantify the carbon intensity of electric vehicles under various traffic flow conditions. The model employs the traffic saturation metric, specifically the <i>v/C</i> ratio, to characterize the traffic conditions. The findings revealed that electric vehicles exhibit lower carbon intensity in congested or unsteady traffic compared to free-flow or steady-flow conditions. Specifically, minimum emissions are achieved at a <i>v/C</i> ratio of 0.96. In contrast to internal combustion engine vehicles, the carbon intensity of electric vehicles is less impacted by traffic congestion, particularly at <i>v/C</i> values exceeding 0.75. Maintaining the <i>v/C</i> values between 0.15 and 0.75 can promote low-carbon operation in mixed traffic conditions. These insights are crucial for reducing carbon emissions in mixed traffic comprising diverse powertrains.