I get you TH. Look at all the adds that make it a point to advertise how fast their car will go to 65mph. It seems to me most fuel loss comes from city driving, with all the stop and go driving. My idea would be to develop better electric cars.
As to the speed, I would not doubt that 55mph is most conservative. Another point; take two cars with same engine and weight, one with an automatic, the other with a manual 5 speed. Say they both have five gears. Now the automatic has to power itself, one waste, the other, one is able to go into high gear and maintain a speed of 50mph, while the automatic will downshift. I think it is baloney that the average car would lug at 50mph in high gear.
If 55mph is a good standard, then maybe we could bring back some angles; I do not like the round bug-shaped cars! The reason I always hear about the need for the bug shape is aerodynamics. There should be little difference in the shape of a car at 55mph? Now if the bug is justified, it has to be that it is able to go faster with the same wind resistance as my old car.
For a while I was considering buying a Corvette; why, not for speed, just for the looks, a basic blue one priced down. The new Cadillac with good looks, well fair looks has an engine over 500 HP, who needs it, but it's pretty. I would consider a little MG type car with a 1200 CC engine if they made one. The last nice looking economy car was the Honda CRX, which the least powerful engine would get 45 mile to a gallon at 60 mph, we had one so I know it would get that on the highway. Why not something like that, but improved today?