Construction of a tunnel that connects the centre of Andorra la Vella with the CG3, in three phases:
Phase I: Excavation of a tunnel (1,262 m). A gallery, 2 metres in diameter, was built, and later converted into the safety evacuation gallery.
Phase II: Excavation of the main tunnel.
Phase III: Interior finishes, installation and commissioning of ventilation, lighting and fire safety systems, among others.