effect of geometric design parameters to improve safety and accidents reduction (case study: sari – kiasar corridor)

background and aim: traffic accident is one of the main causes of mortality in iran. the damage and injury caused by these accidents threatens human societies severely. rural accidents are often more severe and show harsher consequences because the operational speed is higher on rural roads and highways. world statistics presented by world health organization (who) reveal that about 25 percent of all injuries in the world are caused by traffic accidents. appropriate diagnoses and treatments of traffic black spots, prioritization, defining proper safety countermeasures and geometric design improvements are the main objectives of this study. materials and methods: in this study, geometric design parameters are verified in black spots to determine which deficiency is the main cause of safety problem. sari – kiasar corridor, which is a rural road, is selected as the case study. results: because of the fact that the general topography of sari – kiasar corridor is mountainous, the geometric design parameters are very diverse. thus, after evaluation of geometric parameters, black spots are determined according to the types of accidents, severity of accidents, rate of accidents and the collision scenario. these items are then verified and studied in detail. conclusion: results of the assessment show that geometric parameters such as horizontal and vertical curves, poor pavement, poor shoulder quality and poor drainage are contributing factors in increasing accident risk. references aashto a. guide for achieving flexibility in highway design. washington, dc2004. charlton sg. the role of attention in horizontal curves: a comparison of advance warning, delineation, and road marking treatment. accid anal and prev. 2007;39:873-85. gupta rc, jain rp. effect of certain roadway characteristics on accident trates for two-lane roads in connecticut. transport. res rec. 1975(541):50-4. mcdonald n, editor. look and learn: capitalising on individual responsibility in speed management. national conference, australian institute of traffic planning and management; 2004; adelaide,south australia. oxley j, fildes b, corben b, langford j. intersection design for older drivers. transp res part f traffic psychol behav.2006;9(5):335-46. transportation in an aging society: improving mobility and safety for older persons. washington dc, usa: committee report and recommendations. transportation research board, national research council.1988. hauer e. the safety of older persons at intersections. transportation in an aging society, special report 218, transportation research board, national research council. washington dc, usa1988. flahaut b. impact of infrastructure and local environment on road unsafetylogistic modeling with spatial autocorrelation. accid anal prev. 2004 nov; 36(6):1055-66. elvik r. how much do road accidents cost the national economy? accid anal prev. 2000 nov; 32(6):849-51. matthew g. karlaftis, ioannis golias. effects of road geometry and traffic volumeson rural roadway accident rates. accid anal prev. 2002; 34(3):357-65. shankar v, mannering f, barfield w. effect of roadway geometrics and environmental factors on rural freeway accident frequencies.accid anal prev.1995;27(3):371-89. haynes r, lake ir, kingham s, sabel ce, pearce j, barnett r. the influence of road curvature on fatal crashes in new zealand. accid anal prev. 2008 ;40(3):843–50. walmsley d, summersgill i. the relationship between road layout and accidents on modern rural trunk roads. crowthorne: transport research laboratory1998. asgari s. effects of geometric design on the main road traffic accidents in ilam 1995. saffarzadeh m, pouryavari m. modeling of determine road safety index. civil journal of modarres university. 2008;25. arjroudi a, shabani sh. procedures of registration of accidents and identifying high traffic accident points. transportation research institue. 2008. automated traffic counting: office of mazandaran's transportation and terminals province. reprot of transportation2010.