Howdy,
'10 QC Big Horn Hemi w/ 3.92 gears & 275/60-20's
I live in rural Arkansas and with daily driving I'm in the 18.5mpg range with my lead foot.
I can drive to Little Rock and back and average over 20 mpg if I drive the speed limit.
I've made 2 trips to Dallas and I averaged 19.2 and 19.3mpg and that's driving over the speed limit the entire trip, plus stop and go construction traffic driving with 4 adults and luggage w/ the A/C going too.
When the "man" states 20mpg highway mileage he means driving at a steady 55mph on a perfectly flat plane at sea level with a 80lb driver and a tail wind, not driving 75mph with 3 adults and 500lbs of cargo in the hill country.
Paul