All very interesting information but my truck gets some of its best gas mileage at 70 MPH. Why do they do wind tunnel tests if drag is unbeatable?
Wind tunnel tests, test the amount of drag a vehicle has. Wind tunnel tests are performed because drag is the single most important factor for both economy and performance. Making a vehicle areodynamic is always a good thing.
However, even the most areo of vehicles will have more drag at 70mph than it did at 55mph. Should you ever find away to accomplish otherwise, you're just a baby-step away from patenting perpetual motion.