Please cite your so-called studies and the tiime-frame in which the studies were made if you can. Otherwise, I believe the previous posted is correct. At least, that is what my mechanics tell me about our vehicles and we have quite a few in the company.
Like i said, I DONT HAVE studies, IF you do a search on optimal speed MPG or something of that variation. 55MPH seems to be the consensus. I would like a NEW study to see if this is the case. Also I would like to see some sort of CAFE standard put on newer vehicles. It doesnt have to be very intrusive just 3-4 extra MPG... that wouldn't cause any harm. but would reduce our imports on oil a lot.