Yes I've change my commute because of the scan gauge and its instant feedback. I found I have 3 options depending on time of day. I was driving what I though was the best route because of light traffic and higher speeds but it was using more fuel. Between google earth and the scan gauge you can really look at a lot of options if there is more than one way to go to work. The fastest and flatest does not alway use the least fuel( at least for casper).
nah man if city is played right, you can beat your highway epa rating with ease. Its just your time will be required as well as your technique.
on the highway engine load is as high as 50% that's how much of a ***** areodynamic drag is.
hate to break the bad news but on a freeway I can acheive double my street mpg if I wanted. I overcomed drag by installing a belly pan and kept changing the design till it worked just right. I changed the belly's design 3 times now. I also have the undertrays in the front of the car. So far I'm getting around 40mpg on the freeway at 65mph. Next time I will get taller tires and will bump that number up 1-2mpg.