Utah has a lot of changes in elevation. It isn't unusual to have several ten-or-twenty mile inclines and ten-or-twenty mile declines in one 50-mile trip. I was thinking how easy it would be to "cheat" on your gas mileage. You could switch to electric mode, "normal", whenever you were going uphill and switch to gas mode, "hold", when going downhill. You could inflate your gas-only mpg enormously until you run out of charge. That's assuming you want to inflate your gas mileage and don't care about electric mileage. I've been doing this a lot. Not with the intention of cheating, but I think the Volt handles long inclines better in electric mode than in gas mode. It illustrates how hard it is to get meaningful mileage measurements in the Volt.