That's not quite true. Yes, going slower is more efficient, but you're looking at an instantaneous force chart, the car going 80mph will experience approximately double the drag force, but since your travel time has been reduced by 25% at 80 vs 60 you don't double the energy usage. It's actually only about 50% more energy spent fighting drag (2x drag * .75 time = 1.5x)Consider some physics behind this. Looking at the blue curve (Rivian has a low Coefficient of Drag) of an aerodynamic car in this exaple chart, air drag force is under 100 Newtons from 0 to 40. Just to go from 70 to 80, it’s an additional 100 Newtons. You need 25% more energy from 70 to 80 on an aerodynamic vehicle. At 60, you need half the energy, as compared to going 80. Higher Speed has a huge impact on range.