I guess my message was misconstrued - it was more towards people who are disappointed with what their avg. MPG has been thus far and are unhappy with their purchase.
From what I've read a lot more people have been saying they're closer to 13-14 MPG with a similar highway to city split. People like you who are averaging 17 seem to be in fewer in numbers. And then some people mention they're getting close to 20mpg. Obviously the better you do, it should be a pleasant surprise and it should make you happier about your purchase. But I am talking about people who are regretting purchasing this type of vehicle because their fuel efficiency sucks compared to someone like you.
There are too many things to take into consideration that impact everyone differently. For example, I live in New York Tri State area and my highway experience ain't exactly friendly. Plus, I am not driving much on the highway to begin with, and when I do, my smooth sailing at a nice 65-75 mph is usually 20 minutes max if i'm lucky. Maybe closer to 45minutes if I go all the way out east.
But if I didn't know any better - based on people saying they're getting 20 to even 25mpg all on the highway....I would be quite disappointed if that was my expectation. Because where I live, its not. I'd be lucky to get what you're averaging if I solely drove on the highway.
Well, driving environment and habits definitely affect it, for sure.
I live in a ~120k person midwest town, and it is largest city for 100 Mile radius.
Traffic in town is light, normal Midwest stuff...
Highway drives are on fairly sparse highways where I can set the cruise and not touch a pedal for probalby the duration of the trip, save the occasional car to pass on a 2 lane, or a to to slow down for.
Interstate Highway travel is usually set the cruise around 74-76, and don't touch a pedal until the exit at my destination.
For example, I drove 245 miles from my home to Milwaukee 2 weeks ago, the cruise was on ACC and set at 76. We purred along that trip and I literally never turned off the cruise...I averaged 17.6 for that 245 miles. (Reset Trip 1 when I filled up at home, read it in the hotel parking lot in Milwaukee).
Anyway, yes, I agree w/ you...driving environment and style (like if you really love feeling the 6.2 every time you accelerate, and mash it to the floor every time...don't expect my numbers, but do expect a big smile on your face) are the biggest factor in economy.
Anyone who bought one of these rigs should expect 12-15 in all city driving and 16-20 on the road...
Wind is also a factor...
Up side, you are driving down the road in your lazy boy recliner, little to no road noise, and with up to 7 of your friends, vs. taking 2 cars! And you can bring your toys along behind you if you want!