It can be. Fog can greatly reduce visibility for drivers. In thick fog, pedestrians, animals and even other vehicles and traffic signals can be extremely difficult to see. The National Weather Service reports fog when visibility drops below one mile. At this point, drivers can still see fairly well, but must be alert for thicker pockets of fog potentially developing.
In our region, fog sometimes reduces visibility to less than a half-mile over large areas, causing an even greater potential for visibility problems. Occasionally, extremely thick fog develops with visibilities over wide areas reduced to under an eighth of a mile. In pockets, fog locally can grow so thick, you can barely see more than a couple of yards in front of you. A Fog Advisory or Dense Fog Advisory is issued by the NWS when visibility becomes an issue. Advisories are reported on Action News.