The tunnels have been constructed following the NAT method, without top heading and benching, and therefore full face excavated with a total section of 80 m2, and tunnel pulls ranging from 2 to 4 m. The south section of both tubes, excavated in coluvial soils, was also full face excavated, although in the East Tunnel (Tunnel C2) the total section was 158 m2, considering three lane road tunnel. This section was really a challenge and a special care was taken.