Environmental Impact of Commercial E-Trucks on Flexible Pavement

Abstract: The transportation sector accounts for 28% of U.S. greenhouse gas emissions, and flexible pavements are a significant component of this infrastructure. As the freight industry shifts toward the adoption of heavy-duty electric vehicles (HDEVs), its long-term impacts on flexible pavements and the environment demand closer examination. This study evaluates the environmental impacts of HDEVs on flexible pavements through a comprehensive life cycle assessment (LCA). It quantifies carbon emissions across all stages of the pavement life cycle: materials production, construction, use, maintenance, and end-of-life.

The LCA considered four distinct flexible pavement sections, representing interstate highways, arterial roads, and rural roadways in the U.S. One of the critical LCA metrics is the International Roughness Index (IRI) progression for the use phase to evaluate energy consumption. Adjusted IRI progression curves that quantified the impact of HDEVs on pavement distresses were implemented. HDEVs were found to accelerate the deterioration of pavement, leading to a faster increase in the IRI and triggering maintenance sooner compared to conventional diesel-powered trucks. A rougher pavement induced by HDEVs resulted in more frequent maintenance activities and led to higher energy consumption during the use phase. To ensure a fair comparison of energy consumption between HDEVs and conventional diesel-powered trucks, the study followed the Environmental Protection Agency’s recommendation in converting one gallon of gasoline to its equivalent kilowatt-hours of electricity.

By integrating IRI-based energy consumption estimates with carbon emissions from materials production and construction processes, the LCA provided a comprehensive evaluation of the environmental impacts induced by HDEVs. The study identified the environmental trade-offs associated with various pavement structural designs and highlighted their impact on carbon emissions. The findings emphasized the importance of incorporating new truck technologies into pavement design and analysis, as well as their inherent impact on maintenance and rehabilitation schedules, while prioritizing decarbonization strategies.