The route was chosen according to the highest criteria regarding environmental impact, safety, maximum flow and speeds on the route.
Due to the large concentration of natural values and protected ecologically important areas through which the route will run, most of the initially proposed variants turned out to be unacceptable. Taking into account professional guidelines and opinions from public presentations and consideration of variants, the final tunnel variant was created, which was supported by the profession, all local communities and competent ministries.
The Government of the Republic of Slovenia has approved the proposed route of the second track in 2005 Regulations on the National Location Plan.