The project involved the construction of the Uretamendi tunnel, made up of two parallel tunnels, one in each direction, with two carriageways on each.
East Tunnel (axis 42): will have a length of 580.96 m, starting at kilometre 5+080.63 and ending at kilometre 5+669.59.
West Tunnel (axis 43): will have a length of 588.72 m, starting at kilometre 5+078.65 and ending at kilometre 5+667.37.
The tunnel has two interconnecting galleries between both tunnels (axis 43 and axis 43) with a separation distance between 175 and 350 m. These interconnecting galleries allow the evacuation of individuals and access of vehicles to the tunnel.
The tunnels have a total excavation section which varies between 108 m² for the I rock type and 114 m² for the IV rock type.