When I was a soldier in Germany ('72-'73) we were short handed. Since I had a Army License, I drove quite a few "extra" vehicles we took on Reforger, no matter what my real job was ( which vacillated between about four!) anyhow, thats how I always drove, heat blasting, window down, BUT I was a Skoal dipper/tobacco chewer back then (plus smoked cigs and other herbs,,,) so I could spit out the window, ha. The fact we only got a couple hours sleep a night made all that fresh/cold air as necessary as coffee, when you could get either one, you took it! ha