Having rented a new car on my last vacation, one that had all sorts of read outs on speed and fuel efficiency, my best results came out on the open road doing 70-75 mph. Even nudging it up to 80 mph didn't signify a decline in efficiency.
I pay for my own fuel and the taxes too. I pay out of pocket for my personal transportation and the fees and expenses such entailed, as do we all.......and we all pay for idiot politicians' travel and extended costs for their entourage, also out of pocket.
If Hillary wants to do something useful, she can wash my van......cuts down on the drag.