You sure about that? Because I easily get about 70 mpg on my Prius (C class) when I'm supermiling in the city. Granted it's not as efficient on the highway, and unfortunately I do have to do a lot of highway travel. I can sustain a good a 55mpg average at the end of the month though. I plan to start borrowing my wife's whenever I'm on the highway, I think this way I can average mpg in the 70s overall when I do this.