The best mileage ever on a tank was. . .the second tank of gas I put into La Madame Bleu. It included an 80 mile roundtrip down and back from Long Beach, CA to Carlsbad, CA. Some of it was on cruise control.

The terrain is rolling, and on most climbs (I also ride a bike), I could see the mpg display drop down to 14 mpg.

That mpg was 51.

Strange as it seems, the car seems to have degraded in performance after its first service run to Prius at around 4,500 miles.

My best was 50mpg. I drove 100 miles stright on the highway at 60mph. There was some drafting in there too.