That's better--2010 Honda Insight mpg update
Almost three months into ownership of the 2010 Honda Insight, my last fill-up finally met with my expectations--45+ mpg. Ironically, I acheived this without trying to drive maximizing mpg (however, there were about 100 highway miles on this tank).
I had been averaging around 41 mpg on my first three tanks of gas and was somewhat disappointed. One, because the trip computer was reporting over 47 mpg, but doing the actual calculation, it was significantly lower than that. The other reason was I was driving in ECON mode and trying to keep the speedometer indicator in the green (which isn't the most fun driving I've ever done).
This time around, I did keep the car in ECON mode, but drove it with more aggressive accelleration than I had been. Maybe I was getting the benefits of the hypermiling technique of "pulse and glide."

In any case, I hope 45 mpg is the worst mileage I get for the rest of the summer. When the weather cools off, I'm expecting the battery performance, and therefore mpg, to suffer a bit.
So far, so good. The car has all the tech comforts I wanted (GPS, iPod integration, Bluetooth), but I gave up RWD, manual transmission performance to get higher mpg. 45 mpg makes me feel better about the decision.
One note on mpg--it really isn't the best way to measure the fuel efficiency of a vehicle (in an easy to compare way anyhow). Gallons per mile, or gallons per 100 miles makes the math much easier to do in your head when comparing vehicles. See the MPG Illusion for more information.
I'm using 2.38 gallons per 100 miles so far. To put that in comparison, my old car (a 2002 Lexus IS300) was using about 6 gallons to go the same distance. A 2.38 gpm means I can commute to work all week and back using just over 2 gallons of gas. That sounds good to me.

