where v(t) is the truck speed, θ is the road angle calculated from the road grade, c r is the rolling resistance coefficient (0.007 from Zhao et al. ), c D is the drag coefficient (0.6 from Zhao et al. ), A cabin is the area of the truck cabin (9.2 m 2 from Kovacs et al. ). We chose these vehicle parameters to match those of an average long-haul Class 8 tractor-trailer, as used by the U.S. Environmental Protection Agency and the Department of Transportation's National Highway Traffic Safety Administration in their baseline studies on aerodynamic improvements for trucks within the 21st Century Truck Partnership. ρ air represents the density of air used in calculating the vehicle's air resistance, g denotes the acceleration due to gravity, and m is the total vehicle mass. The total vehicle mass is the sum of the curb (empty truck), battery, and payload mass. Figure shows the powertrain considered in this study. The main powertrain components include the gear system, motor-inverter, and battery. Each of these components has an associated inefficiency due to either mechanical losses or electrical resistances, which we account for using efficiency terms (η). Additionally, we consider auxiliary systems such as the battery cooling, accessories, and more which are modeled as a fixed power load (P aux =10 kW). The power required from the battery (P bat ) is given by Equation ,