The project involved the improvement of the Northeast connection between Spain and Portugal. The works also included renovation of the Sierra de Marão crossing.
The overall Transmontana highway project was over 194 kilometers in length, and contains 17 viaducts including:
- “Viaducto del Corgo” with 2,780 meters ilong and a maximum height of 230 meters. Making it the second highest in Europe.
- Bridge over the Tinhela River with at 780 meters long, and a maximum height of 220 meters.