2010 Prius III: Kansas to North Dakota and back
2010 Prius III
3 adults + luggage & gear, say 750 lbs total cargo.
2407.7 miles at displayed 55.6 mpg (52.93 calculated with 4.8% average MID over-report) over the 6-day trip 8/1 to 8/6/10.
Brought lifetime calculated mpg to 50.3 mpg over 12,189 miles since purchase 12/18/09 in spite of 1.5 mile commute by non-hypermiling spouse. I expect small increase in lifetime until cold returns in Jan/Feb.
This trip was probably 60% 2-lane back roads with light traffic and 40% interstates with relatively light traffic. 227 miles were just cruise control at 75 mph psl when we found there are no hotel rooms in western or central N Dakota due to oil drilling boom out west. I estimate taking out of cruise control and slowing to upper 60's increased mpg from around 48 to around 57.5 mpg calculated or about a 20% improvement over this slightly downhill run with rolling hills.
We ran AC pretty much the whole trip, though outside temps were not too high most of the way (mostly 70-85F).
Trip included climbing onto high plains, climbing in Badlands, Mt Rushmore, and Teddy Roosevelt National Park, lots of rolling hills (NE sand hills, KS flint hills, etc). Average speed was 52 mph, which includes significant idling at 0 mph. Highway speeds ranged from 55 to 75, with most in a DWL between 60 and 65.
So, nearly 53 mpg carrying 750 lbs (10% over highway EPA, 6% over combined EPA) without much hypermiling effort. Probably 85% of these roads I had never been on, and 98% were unfamiliar to me. I am pleased with these results. 45.5 gallons of gas is 15 gallons per person. Some gas was ethanol free (many pumps in the Dakotas offer choice: 0, 10, 30, 85% ethanol).