Research efforts on weather effects have been concentrated on snow or rain related crashes, however, there is a lack of good understanding of crashes occurring under fog or smoke (FS). This study presents a comprehensive examination on FS related crashes using crash data in Florida (2003-2007).A three-stage research strategy was implemented so as to 1) identify FS crash prone hotspots, 2) examine FS crash characteristics with respect to temporal distribution, influential factors and crash types, and 3) estimatethe effects of various factors on injury severity given a FS crash has occurred. Ten distinct FS crash hotspots were identified on the state-maintained road network. The morning hours in the months of December to Februaryare the prevalent time for FS crashes. Compared to crashes under clear-visibility conditions, the FS crashes tend to result in more severe injuriesand involve more vehicles. Head-on and rear-end crashes are the two most common crash types in terms of crash risk and severe crashes. These crashes occurred more prevalently on higher speed, undivided, no sidewalk and two-lane rural roads. Moreover, FS crashes tend to occur more likely at night without street light, which also leads to more severe injuries.
Abstract