I don't believe that "Speed Kills," but I do believe that excessive speed wastes gas! E.G., my trusty Benz will get 22mpg at 75, but 28mpg at 60mp[h]
My '98 Ford Countour (4 cyl gas) regularly does 30mpg at 75mph.
That's kinda where I was going with my theory of rewarding those with smaller-engined, lighter cars wih a big tax incentive.
BTW, that's a darn good engine management system. Whose engine actually is a Ford 4-cyl, nowadays?
My '96 Ford Contour (6 cyl gas) regularly does the same.