Cars and wind

[nancylebov]

suecochran was doing a road trip yesterday in fairly high winds, and mentioned that it helps to open the windows (a clever idea I haven't seen mentioned elsewhere) and to go more slowly.

The latter seems intuitively plausible, but why would it work that way? Cars making less contact with the road (micro-bounces) as they go faster is my first guess. Anyone have a more solid theory?