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.
We have a fleet of about 50 cars. Trade them annually with an average of 80,000 miles each. Have for about 30 years. They are driven by our employees traveling all over the U.S. The average daily trip consists of 600 miles.
We have two locations where most maintenance is done except routine oil changes about 5,000 miles. Our fleet consists of several different types of vehicles. Each driver gets to choose from a list which a consulting firm works up based upon the performance of that years cars. We normally buy at the end of the model year to get the best prices.
Based upon our own computer printouts, we find that using cruise-control improves mileage and that we routinely get better performance at speeds in excess of 55 mph than at lower speeds.
In fact, mileage goes down when we get into congested areas. Our computers are now tied into a gps system so that we know where the vehicles are at all times. The worst mileage is obtained in metropolitan areas during rush hours.