Investigation on Spatial and Time Distribution of Frost in Iran and Its Role in Road Transportation

Road accidents are the consequence of combined effect of behavioral, technological and environmental factors. In this paper, the spatial dimension of weather related road accidents is examined using the data extracted from Police Accident Report Forms. Variations in accident frequency in fine weather, rain, storm, fog and snow were detailed and comparison were made between frequency of accident occurrence and weather condition across Iran provinces. Results show that there is a marked correlation between weather related accidents and the geographical distribution of weather conditions. The results also showed that rain was one of the most important factors in road accidents. Most of the winter season accidents occur during the first frost or snowfall due to lack of the road maintenance services. According to obtained results on visibility data; provinces of Fars and Hormozgan in rain, Chaharmahal and Ardebil in snow fall, Ardebil and Zanjan in fog, Sistan and Baluchestan and Yazd in storm conditions were most vulnerable regions.