The best way to get good mileage on the highway is to follow a semi. I did see the MythBuster's episode where they supposedly discounted that, but my 2002 T&C 3.8L has an instantaneous mpg indicator and I get 33 mpg at 65 mph behind a big rig vs 24 mpg normally. I don't follow too close. Indeed, other cars sometimes pull between me and the truck. I usually only do that on a long drive to LA, when I find a truck or motorhome that doesn't have the 55 mph governor common here.