Electrifying Long-Haul Freight—Part I: Review of Drag, Rolling Resistance, and Weight Reduction Potential

Electric heavy-duty tractor-trailers (EHDTT) offer an important option to reduce greenhouse gases (GHG) for the transportation sector. However, to increase the range of the EHDTT, this effort investigates critical vehicle design features that demonstrate a gain in overall freight efficiency of the vehicle. Specifically, factors affecting aerodynamics, rolling resistance, and gross vehicle weight are essential to arrive at practical input parameters for a comprehensive numerical model of the EHDTT, developed by the authors in a subsequent paper. For example, drag reduction devices like skirts, deturbulators, vortex generators, covers, and other commercially available apparatuses result in an aggregated coefficient of drag of 0.367. Furthermore, a mixed utilization of single-wide tires and dual tires allows for an optimized trade-off between low rolling resistance tires, traction, and durability. Lastly, a combination of different lightweight vehicle components manufactured from aluminum and magnesium alloys, carbon fiber composites, titanium, and high-strength steel presents a substantial reduction in overall vehicle weight. Overall, a comparison of a potential EHDTT with a standard Class-8 heavy-duty tractor-trailer (HDTT) reveals a possible reduction in the aerodynamic coefficient of drag by 40%, rolling resistance by 21%, and vehicle weight by approximately 37% prior to electrification. These improvements provide a stronger baseline for electrification to increase the overall range and longevity of an EHDTT making them a more viable option in the market. However, to achieve these advances still requires significant research into commercial feasibility and real-world data under varying conditions with enhanced simulation tools playing a meaningful role.