Quote: "I see most of your mileage is highway. but nice digits nonetheless!"
Thanks for that. Yeah, my "secret" is reasonable driving mostly on the highway.
I bought my 2015 Mazda3 automatic with the 2.0L engine because it was cheap to buy, fun to drive, and among the leaders in its class relative to safety and economy. I drive it 90% on four-lane highways which have speed limits from 55 to 75 mph except for the towns and cities I drive through. My average speed (miles driven divided by elapsed time) is about 56 to 58 mph over my routine run of about 410 miles round trip. My cost per mile is at 4.4 cents according to my Fuelly data, which I find very good.
My main economy effort is speed control. I do not let traffic force me into driving faster than the speed limit, and often I'm a bit below it when traffic is not so heavy as to create a roadblock, especially if there are a lot of slower trucks in the right lane I can drive among; but I never, ever tailgate. I've never gotten a speeding ticket in my life, and the only way I'll get one is by not paying attention.
Sweet cost per mile. Definitely need to pay attention and make it a habit to drive intelligently with speed control even on high traffic. Lots of drivers do that stop - fast accelerate - stop again at tailgating distance. For my truck, I'm getting a wing and a tonneau cover to help with aero dynamics. Should be very helpful against usual high wind resistance and drag.