The Zarzuela junction is on the M-40, over the El Pardo road and the Manzanares river, connecting the M-40 with the M-30 and with the El Pardo road. In a small space are concentrated 2,247.20 linear m of viaducts or 32,760.00 m² of structures.

The choice of prestressed concrete slabs for these viaducts was influenced by the following factors: the increase in spans to reduce the number of piles to a minimum, the arrangement of edges as tight as possible, with compatible slender edges and the play with the shape of the transversal section, with a longer length of the cantilevers to conceal the established edge.