Spatial analysis of traffic accidents using GIS R Biabani GIS Expert Road Transportation& Maintenance Organisation, Iran Email: r-biabani@tto.org S Mesgari Head of GIS Department Khaje nasir university Email: smesgari@yahoo.com Traffic accidents are among most important reasons of death that are either preventable or at least reducible. In Iran, for example, 25% of non-natural death occurrences are caused by traffic accident. They usually cause strong economical and social damages to both the family and the society. Yet, usually road accidents are behavior than in-town accident, mainly because of higher speed. Obviously, in some location, the frequencies of accident are higher. This is mostly related to the special and physical condition of the road, including closeness to intersection, bridge, tunnels, number of lanes and road width, and etc. in this research, the special relation between the accidents location and intensity with some of parameters mentioned above is studied and modeled using GIS. The road between Qazvin- Rasht (in Iran) is selected as the study area which includes a variety of the parameters. Finally, some useful suggestions are made for the reduction of accident potentials and the improvement of road safety.