Fog may slow things down for a while early this morning as visibilities drop to 1/4 mile in some areas. Moist, cool, air trapped near the surface is interacting with the warmer ground temperatures forming the fog. The fog is not widespread, but more patchy in nature, so as you're driving everything might be clear, then in seconds you run into a fog bank that reduces your visibility to just a few yards. These situations tend to cause accidents, especially chain reaction accidents that can involve several vehicles.