Finished an amazing meal at Marlowe in San Fran, found a taxi driver with a Gen III who got me back to the Ferry building FAST. He was like an Armenian Ken Block he was driving so aggressively I appreciate aggressive taxi drivers they save me money!. I took a look at his mpg, 25mpg on a Prius. I couldn't stop laughing as my gf was holding on for dear life.
My wife and I took a Prius cab recently; I felt kinda ill: the guy had the default pic-of-car-with-arrows-going-here-and-there displayed, and basically drove like a maniac. He liked the car, some consolation.
I recently took a cab in SF going between venues for work. (Before I had my own Prius). They definitely do not drive them like they "should" to get the best MPG. They drive to get you from Point A to Point B. Perhaps when they are driving around looking for a fare, they balance out their MPG? The guy I spoke to said he got about 40 MPG average per tank even with all the hills by the Fairmont Hotel. He definitely did not get that on my journey though (from Market Street up to the top of the hill to the Fairmont).