"7. Think Clean. Keeping your car washed and waxed improves aerodynamics and therefore affects fuel economy. Engineer Tom Wagner, Jr. reported to Stretcher.com (as in stretching your dollars) a 7-percent improvement in fuel economy, from 15 to 16 mpg, during a 1,600-mile road trip."
That's the biggest load of **** I've heard lately.
Honestly, if people followed those ten they would save fuel...so let them wax!
2006 Jeep Liberty CRD...Founder of L.O.S.T.
OME 2.25" Lift w/ Toyo Open Country HTs 235/75/16s
ASFIR Alum Eng/Tranny/Transfercase/Fuel Skids
2002 Air Box Mod...Air Tabs (5) on Roof...(3)each behind rear windows
Partial Grill Block with Custom Air Scoop and 3" Open Catback Exhaust
Lambretta UNO150cc 4 Stroke Scooter
Any surface irregularities that a wax job would cover up are buried in the air boundary layer. If you don't believe it, try sprinkling some fine grain sand (Florida beach sand) on the top of your car and drive down the road at 65mph. Those sand grains will still be there when reach the end of your trip (unless you run through some rain).
I dunno, i think it makes sense. I dunno what an air boundary layer is, but it seems to me it would have less friction for the reason basjoos said of the sprinkling of sand on your car, but I suppose pixie dust in the gas tank might be an easier way to improve FE than waxing on a regular basis.