Found this article on how airlines could save 12% in fuel by flying airplanes in formation. See article here:
Taking Cues from Birds to Green the Airline Industry | Triple Pundit
Now, I know, cars wouldn't have an extreme "upwash" like airplanes do - but it made me wonder how close you'd have to drive to a car in front of you to get similar improvements. Mercedes' "distronic" cruise control that keeps a constant distance could be modified to draft people closer than anyone would want to do manually.
Just imagine: Special high-speed drafting lanes could emerge for vehicles with this system! Who needs high speed rail, if you can have high speed automobile trains? (And before anyone answers that last one - yes, I know trains are more efficient, bla-bla-bla - t'was more a rhetorical question...)