I'd take that to the EPA and demand one of those "Low Emissions Vehicle, clean access" stickers that all those prius's have

 

You're on to something, houm_wa--makes me wonder just how high I can get it to read. Need a good hill, which not easy to come by in the Midwest. Given that it only has average, I'll be resetting this a lot in various conditions out of curiosity.

So far, the rate has remained a 12mpg average. I'm guessing the previous 14mpg was wrong, due to a long history of travel?

 

12 mpg around town doing a lot of stop-n-go isn't abnormal. A long highway drive should yield 18 mpg if you reset it once on the freeway and don't pay particular attention to how you drive. If you reset it on the freeway but then pay attention to not speeding excessively and minimizing rapid acceleration and deceleration, you can get over 20 mpg. I have managed to get 22 mpg between Seattle and Portland (~200 miles) many times.

Note: I say minimize decel on the freeway because that usually leads to an accel afterwards!