a study of the effects of road deficiencies on traffic accidents in iran

many researchers have studied different factors effective on traffic accidents. this is, however, among all the factors, road deficiencies have got little attention. in this study we use the results from ‘order logit’ model to review the accident tension model. based on the results, the existence of the studied factors has been effective of the accidents. among the road deficiency factors, lack of safety, has been the most important one. also, non-standard slopes, lack of standard pavement safety, a sudden change in the road shoulder and the tarmac, sharp road bents, lack of proper signs, lack of parking or road shoulders, bad blacktop, lack of vertical signs, lack of light posts and speed humps are among the factors that increase the possibility of car accidents.