On a recent cross country trip that took me 7600 miles around the country, I obtained 8.6 mpg. This was my best fuel economy yet and it didn't come easy. The loads were relatively light; a load of farm tractors, 2 military trucks, a military trailer and a wood chipper, a minesweeper, a load of crane parts and an oversized asphalt paver.
During the entire 7600 mile trip, I only passed 3 trucks as I had the cruise set at 60 mph unless I was in California where the speed limit was 55 mph. At 60 mph, my tachometer stayed around 1300 RPM and I was saving fuel like crazy. I never idled as I have the ParkSmart HVAC system which kept me comfortable no matter where I was; all while not burning fuel.
When I loaded up crane parts in Oakland, CA going over 2800 miles to Maryland, there were 2 other trucks loading up with me for the same trip. I was the last to leave and one of the other trucks passed me twice; once in Nebraska and once in Iowa on the trip across. He was moving at a "high rate of fuel consumption" to say the least. On the day of delivery, that very truck delivered right in front of me in Maryland. I wonder how much fuel that driver wasted as he raced across the country and passed me several times only to get to the destination right in front of me.
No matter what kind of truck and trailer you have, you can improve your fuel economy just by slowing down. It's an easy way to save fuel that requires no expenditures on your part and you can immediately see major improvement.