I just finished processing a batch of photos from a trip last month and some of the shots seem to have excessive noise in them despite shooting at ISO 200. I know I have issues getting the exposure right since the headlights trick the sensor most of the time and the resulting shot comes out too dark. Is this where the noise is being introduced? Any tips to get a more consistent exposure that is not blown out by the headlights? I've included a link to a shot to show what I am talking about. There was some snow in the air and that always seems to turn out noisy when I shoot as well. Any thoughts here? Equipment/Settings: 50D, 70-200L @f8, ISO 200, 1/160.