moose66
Been here awhile...
For those familiar with I-85 through North Carolina, you'll know the average speed is 72-80 mph. At 72-75 mph I get 31-32 mpg. Faster than that, mileage dropped off to 28-29 mpg.
Very familiar with I-85 in VA/NC. You can let loose there between Petersburg and Durham! Watch out for the rough road surfaces though! It's a lot easier to reach those good mileage points there than it is in your neck of the woods. I am a Hampton Roads native, and I know the roads there are clogged unless you are out in the late PM/early AM. For such a large car, the Genesis posts great numbers at a constant 70-80 MPH IMO. Anything other than those speeds, the mileage is just average.