Nice one, Spif!
Optimizing your route is right up there with changing your driving habits as one of the biggest potential gains in mpg without ever having to touch the car. Most people have several routes available, with variations of each one, so the trick is to find that sweet spot where you end up with the best fuel economy.
I tweaked my route in the Festiva until I was finally able to break 60 mpg on a tank, and when I modified my route in my current Insight to include a lot of highway miles, I gained an immediate 5 mpg.
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