Identifying Determinants of Unpermitted Overtaking on Two-Lane, Two-Way Rural Roads in Iran

Previous studies in Iran show that 50 to 60 percent of rural traffic crashes are on two-lane, two-way roads, which constitute 82 percent of road networks in Iran. Since there is no median on this type of road, drivers use the opposite lane for overtaking, which may result in head-on crashes and, consequently, very severe injuries and deaths. Despite the importance of overtaking on two-lane, two-way rural roads, very few studies examined this issue. For traffic injury prevention, this study aims to identify determinants of unpermitted overtaking resulting in head-on collisions on on two-lane, two-way rural roads. The data in this research were gathered by an expert –a transportation engineer– accompanied by patrolling police, through interviews with drivers after permitted or unpermitted overtaking. The analysis of 514 interviews using the Chi-squared test and, subsequently, a binary logistic regression model identified determinants of overtaking on two-lane, two-way rural roads and, therefore, the head-on-crash-prone places. Plotted graphs show that unpermitted overtaking is more frequent in agricultural and arid areas than in residential and industrial areas. In addition, unpermitted overtaking occurs more in plain areas compared to mountainous areas. The increase in the longitudinal slope of the road, the decrease in horizontal curve radius of the road, the decrease in shoulder width, and the increase in driving time with no rest increased the probability of unpermitted overtaking. Furthermore, the frequency of unpermitted overtaking is higher for business trips in comparison with recreational trips. Finally, for any finding some recommendation was provided.


  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; Maps; References; Tables;
  • Pagination: 14p
  • Monograph Title: TRB 95th Annual Meeting Compendium of Papers

Subject/Index Terms

Filing Info

  • Accession Number: 01599035
  • Record Type: Publication
  • Report/Paper Numbers: 16-6494
  • Files: TRIS, TRB, ATRI
  • Created Date: May 17 2016 12:11PM