gang-
Any physics-types out there?

I try to draft busses and trucks, etc as much as possible on my daily ride to work (yes dangerous, but too tempting, fast and fun). Yesterday I manged some serious speed behind a bus accelerating on flatland. Upon telling my significant other we got into the following debate:

-- does the eddie behind the bus actually push me at all? significantly?
-- or was the speed just me in the ~vacuum?

whaddya think?