With the Nascar racers, two are less wind resistance than each separately and added together, so the second car makes the first car move through the air easier, and himself as well.

So the car behind the winnebago may help him along a bit.

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.