I drive a 1999 Chevy Suburban. For the uninitiated, these vehicles (2WD) top out at just over 20MPG. As most of my miles are higway mileage, that's a fair average. Of course, I push for the extra miles by coasting downhill, staying at 55MPH, keeping my tires inflated, etc, etc.
I decided to do a little research into what it would take to buy a "greener" vehicle. As I live in a rural area, there's a lot of open country in which I drive. As I checked out the stats, I quickly realized my vehicle is as good as I'm going to get. I need an 8 seater, and they don't make wagons with that seating capacity. Even the minivan class ranged from 18 to 23 MPG. The SUV's topped out at 24MPG. And with the price tags these vehicles are carrying, I would well into the six digits of miles driven before I would realize any cost savings at all based on fuel consumption.
The automotive industry simply is not making fuel efficient vehicles for large families. And while my family is larger than most, let's not forget a myriad of instances where an efficient large vehicle would be welcome. Church outings, youth group trips, family reunions. The list goes on.
Once we get the truck paid off, I may buy a smaller vehicle for my contract jobs, which can take me 100 miles out or beyond. But as for family vehicles, I think we've gotten as fuel efficient as we're going to get.