The Lavacolla–Arzúa West section of the A-54 motorway comprises 18.5 km of newly constructed infrastructure, functionally replacing the corresponding stretch of the N-547 Lugo–Santiago de Compostela road. The alignment follows a sinuous layout, deliberately routed away from population centers and areas of high agricultural productivity, thereby enhancing road safety and reducing impacts on the surrounding environment, including the historic Camino de Santiago, which runs parallel to the former road.

The project includes the construction of five interchanges of different typologies, incorporating solutions with single or dual roundabouts, ensuring efficient connectivity and traffic flow.

The standard cross-section consists of two roadways separated by a 9 m wide median. Each roadway comprises two 3.50 m lanes, an 2.50 m outer shoulder, and a 1 m inner shoulder.

The pavement structure along the main alignment consists of 15 cm in of bituminous mixtures over 20 cm in of soil-cement. The bituminous layers are arranged in three courses: 3 cm in of M-10, 5 cm in of S-20, and 7 cm in of G-25, ensuring appropriate structural performance and long-term durability.

During construction, certain cut slopes presented stability issues that required the implementation of specific geotechnical measures, including the installation of triple-twist wire mesh, shotcrete reinforced with steel fibers, rock bolting on a 4 x 4 ft grid, removal of large unstable blocks, construction of rockfill retaining walls, and localized regrading of slopes.