The big variable in mpg is what your roads are like. I get pretty bad mileage on my commute to work. Lots of hills, high speed roads, and a whole bunch of stoplights. Nothing kills mileage than having to start at the bottom of a hill, accelerate to 60 and then come to a halt only 1/2 mile later. If your drive is on the flats with no stops then your mileage will be much better.