Quantitative effect of perpendicular proximity of passing traffic on fuel economy

[ShinyMew]

As the title implies, has anyone here measured, or is able to measure, the effect on fuel economy of oncoming traffic, and whether there is a statistically significant or non-negligible positive difference when driving as far to the outside of the lane as possible to maximise the perpendicular distance between the driver and oncoming cars?

[user removed]

I usually move as far right as I can with oncoming traffic anyway, but have never tried to quantify any mileage difference. I think it would be impossible to eliminate the variables unless you went to a track where you could control everything with some semblance of precision.

regards
mech