The biggest problem we have in Montana is "we have two seasons --- 'winter and construction season.'" After the new pavements are laid down, they then seal and chip them. Windshields take a real beating here. So if you don't keep up with the flow, you have those few that have to be in the lead. They fly around you - pull back in front of you - that's where the excess stone chips get flung into your windshield. I'll try to drop down to 77 or 78 and see if that helps. I'm might be and old man, but I don't drive like one...^^^all of the above, but really, if you're having range anxiety in Montana, I'd strongly recommend dropping down from the 80-85mph. Seriously. Even a drop to 75mph would add a significant amount to your range.