Ideal while you have battery charge, though, right? Once you reach a certain point, you've got no battery and therefore you join the "common" cars with above average gas mileage. What I mean is that I can drive 68 and average 50-60 mpg by the computer's reasoning. That's a good number considering that a lot of people here can't hit it. I have been keeping tabs on my tanks since I discovered this site, and while I don't have my signature posted here, I do have it on another site where at this moment I am sitting at a nice 52.xx mpg. You can see my stats listed under the Silver Millenium Falcon. Nearly my entire drive is freeway and while I'm still learning to drive the car with the utmost FE in mind I'd say my numbers are pretty good.