@kelbot it originated before hybrids and during a time of high gas prices. I used to do it all the time, had an extra gauge (and later an app) to track it. Not effective or welcome in heavy traffic...but when you get 40+mpg in a car rated in the low-to-mid 20's, it feels significant. It's gaming your driving, so it's also distracting from the drudgery of the trip.