This paper presents a GIS-based method of spatial analysis that can be applied to the line determination in traffic infrastructure project . It is based on the spatial analysis of the sensitivity or suitability of areas relating to the integration of new infrastructure routes, carefully considering the requirement of intervention optimizing . It makes the comparison of alternatives and a final selection of a"best route " easier, offers new possibilities and simplifies and accelerates the whole process of line determination. The developed method for route-alignment is tried out by an example project for road planing in Germany. It point out that during the line determination all aspects can be equivalently and adequately evaluated. So this method is well suited as a new tool within a line determination procedure and can bring enormous advantages in the planning process of traffic infrastructure projects. projects.