Analysis of Hazardous Fog and Index Development in Korea* Hye-Jin Cho** Abstract : The existing researches related to the fog have focused on mainly the fog itself and its spatial variation. This study defined the hazardous fog as the fog with visibility under 500 m which caused the severe dangerous situation on roads and might cause traffic accident due to insufficient visibility. This study aimed to develop the hazardous fog index which quantified the degree of danger and included frequency of fog, visibility and its duration. We applied the index to 3 years weather station data in Korea and the results showed the distribution of the hazardous fog and their priority in terms of safety management. This was the first study that introduced the fog index in Korea and that quantified the degree of hazardous fog. These application results were useful for identifying the dangerous area due to hazardous fog and contributing to ensure the safety of eventual road users and road authorities. Key Words : Fog, Traffic Accident, Hazardous Index, Visibility (Visiting Lecturer, Department of Geography Education, Korea University, Senior Researcher, Highway Research Department, Korea Institute of Construction Technology), hjcho@kict.re.kr 478
I p I p I p I p I p = f (d w, t p, s p, e p ) (1) d w t p s p, e p 479
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D O N 484
W T W S 2+O HFI = ( N ) W T W S (2) 2 O N W T W S _ 2, D _ D _ < _ 2 D D _ D D _ sd sd sd 2, D _ D _ > 2 sd O N = (, _ 2 2 ) O N ( 4, 8 3, 4 8 W T = 2, 1 4 ) 1, 1 4, 50m ( 3, 50 < 150m ) W S = 2, 150 < 250m 1, 250 < 500m 0, > 500m } 485
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r s = 1 _ 6SD 2 (3) N(D 2_ 1) 487
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