Abstract:

Incorporating cold-start emissions from hybrid electric vehicles (HEVs) into on-road emission modeling is fundamental to accurately assessing the environmental impacts aligned with their projected deployment. This study introduces a cold-start emission model, integrating travel time, dynamic emission rates, and cold-start durations by fuel type. This study further explores the anticipated spatiotemporal patterns of annual cold-start emissions. The study suggests that vehicle electrification could reduce carbon monoxide, hydrocarbon, and nitrogen oxide emissions by over 60% by 2035, despite a significant reliance on gasoline for most on-road vehicles in the next decade. However, cold-start emissions from HEVs will still contribute to 14%, 25%, and 13% of total emissions in 2035. Accurate modeling is crucial for understanding the environmental benefits of vehicle electrification.